| Message ID | 20240418142701.1493091-6-cleger@rivosinc.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | riscv: Add support for Ssdbltrp extension | expand |
On Thu, Apr 18, 2024 at 04:26:44PM +0200, Clément Léger wrote: > Add a small driver to request double trap enabling as well as > registering a SSE handler for double trap. This will also be used by KVM > SBI FWFT extension support to detect if it is possible to enable double > trap in VS-mode. > > Signed-off-by: Clément Léger <cleger@rivosinc.com> > --- > arch/riscv/include/asm/sbi.h | 1 + > drivers/firmware/Kconfig | 7 +++ > drivers/firmware/Makefile | 1 + > drivers/firmware/riscv_dbltrp.c | 95 +++++++++++++++++++++++++++++++++ > include/linux/riscv_dbltrp.h | 19 +++++++ > 5 files changed, 123 insertions(+) > create mode 100644 drivers/firmware/riscv_dbltrp.c > create mode 100644 include/linux/riscv_dbltrp.h > > diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h > index 744aa1796c92..9cd4ca66487c 100644 > --- a/arch/riscv/include/asm/sbi.h > +++ b/arch/riscv/include/asm/sbi.h > @@ -314,6 +314,7 @@ enum sbi_sse_attr_id { > #define SBI_SSE_ATTR_INTERRUPTED_FLAGS_SPIE (1 << 2) > > #define SBI_SSE_EVENT_LOCAL_RAS 0x00000000 > +#define SBI_SSE_EVENT_LOCAL_DOUBLE_TRAP 0x00000001 > #define SBI_SSE_EVENT_GLOBAL_RAS 0x00008000 > #define SBI_SSE_EVENT_LOCAL_PMU 0x00010000 > #define SBI_SSE_EVENT_LOCAL_SOFTWARE 0xffff0000 > diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig > index 59f611288807..a037f6e89942 100644 > --- a/drivers/firmware/Kconfig > +++ b/drivers/firmware/Kconfig > @@ -197,6 +197,13 @@ config RISCV_SSE_TEST > Select if you want to enable SSE extension testing at boot time. > This will run a series of test which verifies SSE sanity. > > +config RISCV_DBLTRP > + bool "Enable Double trap handling" > + depends on RISCV_SSE && RISCV_SBI > + default n > + help > + Select if you want to enable SSE double trap handler. > + > config SYSFB > bool > select BOOT_VESA_SUPPORT > diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile > index fb7b0c08c56d..ad67a1738c0f 100644 > --- a/drivers/firmware/Makefile > +++ b/drivers/firmware/Makefile > @@ -18,6 +18,7 @@ obj-$(CONFIG_RASPBERRYPI_FIRMWARE) += raspberrypi.o > obj-$(CONFIG_FW_CFG_SYSFS) += qemu_fw_cfg.o > obj-$(CONFIG_RISCV_SSE) += riscv_sse.o > obj-$(CONFIG_RISCV_SSE_TEST) += riscv_sse_test.o > +obj-$(CONFIG_RISCV_DBLTRP) += riscv_dbltrp.o As previously mentioned, I'd like to see all of these riscv specific things in a riscv directory. > obj-$(CONFIG_SYSFB) += sysfb.o > obj-$(CONFIG_SYSFB_SIMPLEFB) += sysfb_simplefb.o > obj-$(CONFIG_TI_SCI_PROTOCOL) += ti_sci.o > diff --git a/drivers/firmware/riscv_dbltrp.c b/drivers/firmware/riscv_dbltrp.c > new file mode 100644 > index 000000000000..72f9a067e87a > --- /dev/null > +++ b/drivers/firmware/riscv_dbltrp.c > @@ -0,0 +1,95 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Copyright (C) 2023 Rivos Inc. > + */ > + > +#define pr_fmt(fmt) "riscv-dbltrp: " fmt > + > +#include <linux/cpu.h> > +#include <linux/init.h> > +#include <linux/riscv_dbltrp.h> > +#include <linux/riscv_sse.h> > + > +#include <asm/sbi.h> > + > +static bool double_trap_enabled; > + > +static int riscv_sse_dbltrp_handle(uint32_t evt, void *arg, > + struct pt_regs *regs) > +{ > + __show_regs(regs); > + panic("Double trap !\n"); > + > + return 0; > +} > + > +struct cpu_dbltrp_data { > + int error; > +}; > + > +static void > +sbi_cpu_enable_double_trap(void *data) This should easily fit on one line. > +{ > + struct sbiret ret; > + struct cpu_dbltrp_data *cdd = data; > + > + ret = sbi_ecall(SBI_EXT_FWFT, SBI_EXT_FWFT_SET, > + SBI_FWFT_DOUBLE_TRAP_ENABLE, 1, 0, 0, 0, 0); > + > + if (ret.error) { > + cdd->error = 1; If this is a boolean, make it a boolean please. All the code in this patch treats it as one. > + pr_err("Failed to enable double trap on cpu %d\n", smp_processor_id()); > + } > +} > + > +static int sbi_enable_double_trap(void) > +{ > + struct cpu_dbltrp_data cdd = {0}; > + > + on_each_cpu(sbi_cpu_enable_double_trap, &cdd, 1); > + if (cdd.error) > + return -1; Can this be an errno please? > + > + double_trap_enabled = true; > + > + return 0; > +} > + > +bool riscv_double_trap_enabled(void) > +{ > + return double_trap_enabled; > +} > +EXPORT_SYMBOL(riscv_double_trap_enabled); Can we just use double_trap everywhere? dbltrp reads like sound that a beatboxer would make and this looks a lot nicer than the other functions in the file... > + > +static int __init riscv_dbltrp(void) I think this function is missing an action work - init or probe? > +{ > + struct sse_event *evt; > + > + if (!riscv_has_extension_unlikely(RISCV_ISA_EXT_SSDBLTRP)) { > + pr_err("Ssdbltrp extension not available\n"); > + return 1; > + } > + > + if (!sbi_probe_extension(SBI_EXT_FWFT)) { > + pr_err("Can not enable double trap, SBI_EXT_FWFT is not available\n"); > + return 1; > + } > + > + if (sbi_enable_double_trap()) { > + pr_err("Failed to enable double trap on all cpus\n"); > + return 1; Why do we return 1s here, but an errno via PTR_ERR() below? Shouldn't all of these be returning a negative errono? This particular one should probably propagate the error it got from sbi_enable_double_trap(). Cheers, Conor. > + } > + > + evt = sse_event_register(SBI_SSE_EVENT_LOCAL_DOUBLE_TRAP, 0, > + riscv_sse_dbltrp_handle, NULL); > + if (IS_ERR(evt)) { > + pr_err("SSE double trap register failed\n"); > + return PTR_ERR(evt); > + } > + > + sse_event_enable(evt); > + pr_info("Double trap handling registered\n"); > + > + return 0; > +} > +device_initcall(riscv_dbltrp); > diff --git a/include/linux/riscv_dbltrp.h b/include/linux/riscv_dbltrp.h > new file mode 100644 > index 000000000000..6de4f43fae6b > --- /dev/null > +++ b/include/linux/riscv_dbltrp.h > @@ -0,0 +1,19 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * Copyright (C) 2023 Rivos Inc. > + */ > + > +#ifndef __LINUX_RISCV_DBLTRP_H > +#define __LINUX_RISCV_DBLTRP_H > + > +#if defined(CONFIG_RISCV_DBLTRP) > +bool riscv_double_trap_enabled(void); > +#else > + > +static inline bool riscv_double_trap_enabled(void) > +{ > + return false; > +} > +#endif > + > +#endif /* __LINUX_RISCV_DBLTRP_H */ > -- > 2.43.0 >
On 23/04/2024 18:39, Conor Dooley wrote: > On Thu, Apr 18, 2024 at 04:26:44PM +0200, Clément Léger wrote: >> Add a small driver to request double trap enabling as well as >> registering a SSE handler for double trap. This will also be used by KVM >> SBI FWFT extension support to detect if it is possible to enable double >> trap in VS-mode. >> >> Signed-off-by: Clément Léger <cleger@rivosinc.com> >> --- >> arch/riscv/include/asm/sbi.h | 1 + >> drivers/firmware/Kconfig | 7 +++ >> drivers/firmware/Makefile | 1 + >> drivers/firmware/riscv_dbltrp.c | 95 +++++++++++++++++++++++++++++++++ >> include/linux/riscv_dbltrp.h | 19 +++++++ >> 5 files changed, 123 insertions(+) >> create mode 100644 drivers/firmware/riscv_dbltrp.c >> create mode 100644 include/linux/riscv_dbltrp.h >> >> diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h >> index 744aa1796c92..9cd4ca66487c 100644 >> --- a/arch/riscv/include/asm/sbi.h >> +++ b/arch/riscv/include/asm/sbi.h >> @@ -314,6 +314,7 @@ enum sbi_sse_attr_id { >> #define SBI_SSE_ATTR_INTERRUPTED_FLAGS_SPIE (1 << 2) >> >> #define SBI_SSE_EVENT_LOCAL_RAS 0x00000000 >> +#define SBI_SSE_EVENT_LOCAL_DOUBLE_TRAP 0x00000001 >> #define SBI_SSE_EVENT_GLOBAL_RAS 0x00008000 >> #define SBI_SSE_EVENT_LOCAL_PMU 0x00010000 >> #define SBI_SSE_EVENT_LOCAL_SOFTWARE 0xffff0000 >> diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig >> index 59f611288807..a037f6e89942 100644 >> --- a/drivers/firmware/Kconfig >> +++ b/drivers/firmware/Kconfig >> @@ -197,6 +197,13 @@ config RISCV_SSE_TEST >> Select if you want to enable SSE extension testing at boot time. >> This will run a series of test which verifies SSE sanity. >> >> +config RISCV_DBLTRP >> + bool "Enable Double trap handling" >> + depends on RISCV_SSE && RISCV_SBI >> + default n >> + help >> + Select if you want to enable SSE double trap handler. >> + >> config SYSFB >> bool >> select BOOT_VESA_SUPPORT >> diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile >> index fb7b0c08c56d..ad67a1738c0f 100644 >> --- a/drivers/firmware/Makefile >> +++ b/drivers/firmware/Makefile >> @@ -18,6 +18,7 @@ obj-$(CONFIG_RASPBERRYPI_FIRMWARE) += raspberrypi.o >> obj-$(CONFIG_FW_CFG_SYSFS) += qemu_fw_cfg.o >> obj-$(CONFIG_RISCV_SSE) += riscv_sse.o >> obj-$(CONFIG_RISCV_SSE_TEST) += riscv_sse_test.o >> +obj-$(CONFIG_RISCV_DBLTRP) += riscv_dbltrp.o > > As previously mentioned, I'd like to see all of these riscv specific > things in a riscv directory. Acked, I was not aware of that. > >> obj-$(CONFIG_SYSFB) += sysfb.o >> obj-$(CONFIG_SYSFB_SIMPLEFB) += sysfb_simplefb.o >> obj-$(CONFIG_TI_SCI_PROTOCOL) += ti_sci.o >> diff --git a/drivers/firmware/riscv_dbltrp.c b/drivers/firmware/riscv_dbltrp.c >> new file mode 100644 >> index 000000000000..72f9a067e87a >> --- /dev/null >> +++ b/drivers/firmware/riscv_dbltrp.c >> @@ -0,0 +1,95 @@ >> +// SPDX-License-Identifier: GPL-2.0-only >> +/* >> + * Copyright (C) 2023 Rivos Inc. >> + */ >> + >> +#define pr_fmt(fmt) "riscv-dbltrp: " fmt >> + >> +#include <linux/cpu.h> >> +#include <linux/init.h> >> +#include <linux/riscv_dbltrp.h> >> +#include <linux/riscv_sse.h> >> + >> +#include <asm/sbi.h> >> + >> +static bool double_trap_enabled; >> + >> +static int riscv_sse_dbltrp_handle(uint32_t evt, void *arg, >> + struct pt_regs *regs) >> +{ >> + __show_regs(regs); >> + panic("Double trap !\n"); >> + >> + return 0; >> +} >> + >> +struct cpu_dbltrp_data { >> + int error; >> +}; >> + >> +static void >> +sbi_cpu_enable_double_trap(void *data) > > This should easily fit on one line. > >> +{ >> + struct sbiret ret; >> + struct cpu_dbltrp_data *cdd = data; >> + >> + ret = sbi_ecall(SBI_EXT_FWFT, SBI_EXT_FWFT_SET, >> + SBI_FWFT_DOUBLE_TRAP_ENABLE, 1, 0, 0, 0, 0); >> + >> + if (ret.error) { >> + cdd->error = 1; > > If this is a boolean, make it a boolean please. All the code in this > patch treats it as one. > >> + pr_err("Failed to enable double trap on cpu %d\n", smp_processor_id()); >> + } >> +} >> + >> +static int sbi_enable_double_trap(void) >> +{ >> + struct cpu_dbltrp_data cdd = {0}; >> + >> + on_each_cpu(sbi_cpu_enable_double_trap, &cdd, 1); >> + if (cdd.error) >> + return -1; > > Can this be an errno please? > >> + >> + double_trap_enabled = true; >> + >> + return 0; >> +} >> + >> +bool riscv_double_trap_enabled(void) >> +{ >> + return double_trap_enabled; >> +} >> +EXPORT_SYMBOL(riscv_double_trap_enabled); > > Can we just use double_trap everywhere? dbltrp reads like sound that a > beatboxer would make and this looks a lot nicer than the other functions > in the file... Ahah you gave me a good laugh :D > >> + >> +static int __init riscv_dbltrp(void) > > I think this function is missing an action work - init or probe? > >> +{ >> + struct sse_event *evt; >> + >> + if (!riscv_has_extension_unlikely(RISCV_ISA_EXT_SSDBLTRP)) { >> + pr_err("Ssdbltrp extension not available\n"); >> + return 1; >> + } >> + >> + if (!sbi_probe_extension(SBI_EXT_FWFT)) { >> + pr_err("Can not enable double trap, SBI_EXT_FWFT is not available\n"); >> + return 1; >> + } >> + >> + if (sbi_enable_double_trap()) { >> + pr_err("Failed to enable double trap on all cpus\n"); >> + return 1; > > Why do we return 1s here, but an errno via PTR_ERR() below? > Shouldn't all of these be returning a negative errono? > This particular one should probably propagate the error it got from > sbi_enable_double_trap(). Indeed, I'll use some errno everywhere. Thanks, Clément > > Cheers, > Conor. > >> + } >> + >> + evt = sse_event_register(SBI_SSE_EVENT_LOCAL_DOUBLE_TRAP, 0, >> + riscv_sse_dbltrp_handle, NULL); >> + if (IS_ERR(evt)) { >> + pr_err("SSE double trap register failed\n"); >> + return PTR_ERR(evt); >> + } >> + >> + sse_event_enable(evt); >> + pr_info("Double trap handling registered\n"); >> + >> + return 0; >> +} >> +device_initcall(riscv_dbltrp); >> diff --git a/include/linux/riscv_dbltrp.h b/include/linux/riscv_dbltrp.h >> new file mode 100644 >> index 000000000000..6de4f43fae6b >> --- /dev/null >> +++ b/include/linux/riscv_dbltrp.h >> @@ -0,0 +1,19 @@ >> +/* SPDX-License-Identifier: GPL-2.0 */ >> +/* >> + * Copyright (C) 2023 Rivos Inc. >> + */ >> + >> +#ifndef __LINUX_RISCV_DBLTRP_H >> +#define __LINUX_RISCV_DBLTRP_H >> + >> +#if defined(CONFIG_RISCV_DBLTRP) >> +bool riscv_double_trap_enabled(void); >> +#else >> + >> +static inline bool riscv_double_trap_enabled(void) >> +{ >> + return false; >> +} >> +#endif >> + >> +#endif /* __LINUX_RISCV_DBLTRP_H */ >> -- >> 2.43.0 >>
On Thu, Apr 18, 2024 at 04:26:44PM +0200, Clément Léger wrote: >Add a small driver to request double trap enabling as well as >registering a SSE handler for double trap. This will also be used by KVM >SBI FWFT extension support to detect if it is possible to enable double >trap in VS-mode. > >Signed-off-by: Clément Léger <cleger@rivosinc.com> >--- > arch/riscv/include/asm/sbi.h | 1 + > drivers/firmware/Kconfig | 7 +++ > drivers/firmware/Makefile | 1 + > drivers/firmware/riscv_dbltrp.c | 95 +++++++++++++++++++++++++++++++++ > include/linux/riscv_dbltrp.h | 19 +++++++ > 5 files changed, 123 insertions(+) > create mode 100644 drivers/firmware/riscv_dbltrp.c > create mode 100644 include/linux/riscv_dbltrp.h > >diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h >index 744aa1796c92..9cd4ca66487c 100644 >--- a/arch/riscv/include/asm/sbi.h >+++ b/arch/riscv/include/asm/sbi.h >@@ -314,6 +314,7 @@ enum sbi_sse_attr_id { > #define SBI_SSE_ATTR_INTERRUPTED_FLAGS_SPIE (1 << 2) > > #define SBI_SSE_EVENT_LOCAL_RAS 0x00000000 >+#define SBI_SSE_EVENT_LOCAL_DOUBLE_TRAP 0x00000001 > #define SBI_SSE_EVENT_GLOBAL_RAS 0x00008000 > #define SBI_SSE_EVENT_LOCAL_PMU 0x00010000 > #define SBI_SSE_EVENT_LOCAL_SOFTWARE 0xffff0000 >diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig >index 59f611288807..a037f6e89942 100644 >--- a/drivers/firmware/Kconfig >+++ b/drivers/firmware/Kconfig >@@ -197,6 +197,13 @@ config RISCV_SSE_TEST > Select if you want to enable SSE extension testing at boot time. > This will run a series of test which verifies SSE sanity. > >+config RISCV_DBLTRP >+ bool "Enable Double trap handling" >+ depends on RISCV_SSE && RISCV_SBI >+ default n >+ help >+ Select if you want to enable SSE double trap handler. >+ > config SYSFB > bool > select BOOT_VESA_SUPPORT >diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile >index fb7b0c08c56d..ad67a1738c0f 100644 >--- a/drivers/firmware/Makefile >+++ b/drivers/firmware/Makefile >@@ -18,6 +18,7 @@ obj-$(CONFIG_RASPBERRYPI_FIRMWARE) += raspberrypi.o > obj-$(CONFIG_FW_CFG_SYSFS) += qemu_fw_cfg.o > obj-$(CONFIG_RISCV_SSE) += riscv_sse.o > obj-$(CONFIG_RISCV_SSE_TEST) += riscv_sse_test.o >+obj-$(CONFIG_RISCV_DBLTRP) += riscv_dbltrp.o > obj-$(CONFIG_SYSFB) += sysfb.o > obj-$(CONFIG_SYSFB_SIMPLEFB) += sysfb_simplefb.o > obj-$(CONFIG_TI_SCI_PROTOCOL) += ti_sci.o >diff --git a/drivers/firmware/riscv_dbltrp.c b/drivers/firmware/riscv_dbltrp.c >new file mode 100644 >index 000000000000..72f9a067e87a >--- /dev/null >+++ b/drivers/firmware/riscv_dbltrp.c >@@ -0,0 +1,95 @@ >+// SPDX-License-Identifier: GPL-2.0-only >+/* >+ * Copyright (C) 2023 Rivos Inc. >+ */ nit: fix copyright year >+ >+#define pr_fmt(fmt) "riscv-dbltrp: " fmt >+ >+#include <linux/cpu.h> >+#include <linux/init.h> >+#include <linux/riscv_dbltrp.h> >+#include <linux/riscv_sse.h> >+ >+#include <asm/sbi.h> >+ >+static bool double_trap_enabled; >+ >+static int riscv_sse_dbltrp_handle(uint32_t evt, void *arg, >+ struct pt_regs *regs) >+{ >+ __show_regs(regs); >+ panic("Double trap !\n"); >+ >+ return 0; Curious: Does panic return? What's the point of returning from here? >+} >+ >+struct cpu_dbltrp_data { >+ int error; >+}; >+ >+static void >+sbi_cpu_enable_double_trap(void *data) >+{ >+ struct sbiret ret; >+ struct cpu_dbltrp_data *cdd = data; >+ >+ ret = sbi_ecall(SBI_EXT_FWFT, SBI_EXT_FWFT_SET, >+ SBI_FWFT_DOUBLE_TRAP_ENABLE, 1, 0, 0, 0, 0); >+ >+ if (ret.error) { >+ cdd->error = 1; >+ pr_err("Failed to enable double trap on cpu %d\n", smp_processor_id()); >+ } >+} >+ >+static int sbi_enable_double_trap(void) >+{ >+ struct cpu_dbltrp_data cdd = {0}; >+ >+ on_each_cpu(sbi_cpu_enable_double_trap, &cdd, 1); >+ if (cdd.error) >+ return -1; There is a bug here. If `sbi_cpu_enable_double_trap` failed on all cpus but last cpu. Then cdd.error would not record error and will be reflect as if double trap was enabled. Its less likely to happen that FW would return success for one cpu and fail for others. But there is non-zero probablity here. >+ >+ double_trap_enabled = true; >+ >+ return 0; >+} >+ >+bool riscv_double_trap_enabled(void) >+{ >+ return double_trap_enabled; >+} >+EXPORT_SYMBOL(riscv_double_trap_enabled); >+ >+static int __init riscv_dbltrp(void) >+{ >+ struct sse_event *evt; >+ >+ if (!riscv_has_extension_unlikely(RISCV_ISA_EXT_SSDBLTRP)) { >+ pr_err("Ssdbltrp extension not available\n"); >+ return 1; >+ } >+ >+ if (!sbi_probe_extension(SBI_EXT_FWFT)) { >+ pr_err("Can not enable double trap, SBI_EXT_FWFT is not available\n"); >+ return 1; >+ } >+ >+ if (sbi_enable_double_trap()) { >+ pr_err("Failed to enable double trap on all cpus\n"); >+ return 1; >+ } >+ >+ evt = sse_event_register(SBI_SSE_EVENT_LOCAL_DOUBLE_TRAP, 0, >+ riscv_sse_dbltrp_handle, NULL); >+ if (IS_ERR(evt)) { >+ pr_err("SSE double trap register failed\n"); >+ return PTR_ERR(evt); >+ } >+ >+ sse_event_enable(evt); >+ pr_info("Double trap handling registered\n"); >+ >+ return 0; >+} >+device_initcall(riscv_dbltrp); >diff --git a/include/linux/riscv_dbltrp.h b/include/linux/riscv_dbltrp.h >new file mode 100644 >index 000000000000..6de4f43fae6b >--- /dev/null >+++ b/include/linux/riscv_dbltrp.h >@@ -0,0 +1,19 @@ >+/* SPDX-License-Identifier: GPL-2.0 */ >+/* >+ * Copyright (C) 2023 Rivos Inc. >+ */ >+ >+#ifndef __LINUX_RISCV_DBLTRP_H >+#define __LINUX_RISCV_DBLTRP_H >+ >+#if defined(CONFIG_RISCV_DBLTRP) >+bool riscv_double_trap_enabled(void); >+#else >+ >+static inline bool riscv_double_trap_enabled(void) >+{ >+ return false; >+} >+#endif >+ >+#endif /* __LINUX_RISCV_DBLTRP_H */ >-- >2.43.0 > >
On 27/04/2024 01:59, Deepak Gupta wrote: > On Thu, Apr 18, 2024 at 04:26:44PM +0200, Clément Léger wrote: >> Add a small driver to request double trap enabling as well as >> registering a SSE handler for double trap. This will also be used by KVM >> SBI FWFT extension support to detect if it is possible to enable double >> trap in VS-mode. >> >> Signed-off-by: Clément Léger <cleger@rivosinc.com> >> --- >> arch/riscv/include/asm/sbi.h | 1 + >> drivers/firmware/Kconfig | 7 +++ >> drivers/firmware/Makefile | 1 + >> drivers/firmware/riscv_dbltrp.c | 95 +++++++++++++++++++++++++++++++++ >> include/linux/riscv_dbltrp.h | 19 +++++++ >> 5 files changed, 123 insertions(+) >> create mode 100644 drivers/firmware/riscv_dbltrp.c >> create mode 100644 include/linux/riscv_dbltrp.h >> >> diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h >> index 744aa1796c92..9cd4ca66487c 100644 >> --- a/arch/riscv/include/asm/sbi.h >> +++ b/arch/riscv/include/asm/sbi.h >> @@ -314,6 +314,7 @@ enum sbi_sse_attr_id { >> #define SBI_SSE_ATTR_INTERRUPTED_FLAGS_SPIE (1 << 2) >> >> #define SBI_SSE_EVENT_LOCAL_RAS 0x00000000 >> +#define SBI_SSE_EVENT_LOCAL_DOUBLE_TRAP 0x00000001 >> #define SBI_SSE_EVENT_GLOBAL_RAS 0x00008000 >> #define SBI_SSE_EVENT_LOCAL_PMU 0x00010000 >> #define SBI_SSE_EVENT_LOCAL_SOFTWARE 0xffff0000 >> diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig >> index 59f611288807..a037f6e89942 100644 >> --- a/drivers/firmware/Kconfig >> +++ b/drivers/firmware/Kconfig >> @@ -197,6 +197,13 @@ config RISCV_SSE_TEST >> Select if you want to enable SSE extension testing at boot time. >> This will run a series of test which verifies SSE sanity. >> >> +config RISCV_DBLTRP >> + bool "Enable Double trap handling" >> + depends on RISCV_SSE && RISCV_SBI >> + default n >> + help >> + Select if you want to enable SSE double trap handler. >> + >> config SYSFB >> bool >> select BOOT_VESA_SUPPORT >> diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile >> index fb7b0c08c56d..ad67a1738c0f 100644 >> --- a/drivers/firmware/Makefile >> +++ b/drivers/firmware/Makefile >> @@ -18,6 +18,7 @@ obj-$(CONFIG_RASPBERRYPI_FIRMWARE) += raspberrypi.o >> obj-$(CONFIG_FW_CFG_SYSFS) += qemu_fw_cfg.o >> obj-$(CONFIG_RISCV_SSE) += riscv_sse.o >> obj-$(CONFIG_RISCV_SSE_TEST) += riscv_sse_test.o >> +obj-$(CONFIG_RISCV_DBLTRP) += riscv_dbltrp.o >> obj-$(CONFIG_SYSFB) += sysfb.o >> obj-$(CONFIG_SYSFB_SIMPLEFB) += sysfb_simplefb.o >> obj-$(CONFIG_TI_SCI_PROTOCOL) += ti_sci.o >> diff --git a/drivers/firmware/riscv_dbltrp.c >> b/drivers/firmware/riscv_dbltrp.c >> new file mode 100644 >> index 000000000000..72f9a067e87a >> --- /dev/null >> +++ b/drivers/firmware/riscv_dbltrp.c >> @@ -0,0 +1,95 @@ >> +// SPDX-License-Identifier: GPL-2.0-only >> +/* >> + * Copyright (C) 2023 Rivos Inc. >> + */ > > nit: fix copyright year >> + >> +#define pr_fmt(fmt) "riscv-dbltrp: " fmt >> + >> +#include <linux/cpu.h> >> +#include <linux/init.h> >> +#include <linux/riscv_dbltrp.h> >> +#include <linux/riscv_sse.h> >> + >> +#include <asm/sbi.h> >> + >> +static bool double_trap_enabled; >> + >> +static int riscv_sse_dbltrp_handle(uint32_t evt, void *arg, >> + struct pt_regs *regs) >> +{ >> + __show_regs(regs); >> + panic("Double trap !\n"); >> + >> + return 0; > Curious: > Does panic return? > What's the point of returning from here? Hi Deepak, No, panic() does not return and indeed, the "return 0" is useless. It's a leftover of a previous implementation without panic in order to keep GCC mouth shut ;). > >> +} >> + >> +struct cpu_dbltrp_data { >> + int error; >> +}; >> + >> +static void >> +sbi_cpu_enable_double_trap(void *data) >> +{ >> + struct sbiret ret; >> + struct cpu_dbltrp_data *cdd = data; >> + >> + ret = sbi_ecall(SBI_EXT_FWFT, SBI_EXT_FWFT_SET, >> + SBI_FWFT_DOUBLE_TRAP_ENABLE, 1, 0, 0, 0, 0); >> + >> + if (ret.error) { >> + cdd->error = 1; >> + pr_err("Failed to enable double trap on cpu %d\n", >> smp_processor_id()); >> + } >> +} >> + >> +static int sbi_enable_double_trap(void) >> +{ >> + struct cpu_dbltrp_data cdd = {0}; >> + >> + on_each_cpu(sbi_cpu_enable_double_trap, &cdd, 1); >> + if (cdd.error) >> + return -1; > > There is a bug here. If `sbi_cpu_enable_double_trap` failed on all cpus > but last cpu. > Then cdd.error would not record error and will be reflect as if double > trap was enabled. cdd.error is only written in case of error by the per-cpu callbacks, so it is only set if enabled failed. Is there something I'm missing ? Thanks, Clément > > Its less likely to happen that FW would return success for one cpu and > fail for others. > But there is non-zero probablity here. >
On Tue, May 14, 2024 at 10:06:31AM +0200, Clément Léger wrote: > > >On 27/04/2024 01:59, Deepak Gupta wrote: >> On Thu, Apr 18, 2024 at 04:26:44PM +0200, Clément Léger wrote: >>> Add a small driver to request double trap enabling as well as >>> registering a SSE handler for double trap. This will also be used by KVM >>> SBI FWFT extension support to detect if it is possible to enable double >>> trap in VS-mode. >>> >>> Signed-off-by: Clément Léger <cleger@rivosinc.com> >>> --- >>> arch/riscv/include/asm/sbi.h | 1 + >>> drivers/firmware/Kconfig | 7 +++ >>> drivers/firmware/Makefile | 1 + >>> drivers/firmware/riscv_dbltrp.c | 95 +++++++++++++++++++++++++++++++++ >>> include/linux/riscv_dbltrp.h | 19 +++++++ >>> 5 files changed, 123 insertions(+) >>> create mode 100644 drivers/firmware/riscv_dbltrp.c >>> create mode 100644 include/linux/riscv_dbltrp.h >>> >>> diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h >>> index 744aa1796c92..9cd4ca66487c 100644 >>> --- a/arch/riscv/include/asm/sbi.h >>> +++ b/arch/riscv/include/asm/sbi.h >>> @@ -314,6 +314,7 @@ enum sbi_sse_attr_id { >>> #define SBI_SSE_ATTR_INTERRUPTED_FLAGS_SPIE (1 << 2) >>> >>> #define SBI_SSE_EVENT_LOCAL_RAS 0x00000000 >>> +#define SBI_SSE_EVENT_LOCAL_DOUBLE_TRAP 0x00000001 >>> #define SBI_SSE_EVENT_GLOBAL_RAS 0x00008000 >>> #define SBI_SSE_EVENT_LOCAL_PMU 0x00010000 >>> #define SBI_SSE_EVENT_LOCAL_SOFTWARE 0xffff0000 >>> diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig >>> index 59f611288807..a037f6e89942 100644 >>> --- a/drivers/firmware/Kconfig >>> +++ b/drivers/firmware/Kconfig >>> @@ -197,6 +197,13 @@ config RISCV_SSE_TEST >>> Select if you want to enable SSE extension testing at boot time. >>> This will run a series of test which verifies SSE sanity. >>> >>> +config RISCV_DBLTRP >>> + bool "Enable Double trap handling" >>> + depends on RISCV_SSE && RISCV_SBI >>> + default n >>> + help >>> + Select if you want to enable SSE double trap handler. >>> + >>> config SYSFB >>> bool >>> select BOOT_VESA_SUPPORT >>> diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile >>> index fb7b0c08c56d..ad67a1738c0f 100644 >>> --- a/drivers/firmware/Makefile >>> +++ b/drivers/firmware/Makefile >>> @@ -18,6 +18,7 @@ obj-$(CONFIG_RASPBERRYPI_FIRMWARE) += raspberrypi.o >>> obj-$(CONFIG_FW_CFG_SYSFS) += qemu_fw_cfg.o >>> obj-$(CONFIG_RISCV_SSE) += riscv_sse.o >>> obj-$(CONFIG_RISCV_SSE_TEST) += riscv_sse_test.o >>> +obj-$(CONFIG_RISCV_DBLTRP) += riscv_dbltrp.o >>> obj-$(CONFIG_SYSFB) += sysfb.o >>> obj-$(CONFIG_SYSFB_SIMPLEFB) += sysfb_simplefb.o >>> obj-$(CONFIG_TI_SCI_PROTOCOL) += ti_sci.o >>> diff --git a/drivers/firmware/riscv_dbltrp.c >>> b/drivers/firmware/riscv_dbltrp.c >>> new file mode 100644 >>> index 000000000000..72f9a067e87a >>> --- /dev/null >>> +++ b/drivers/firmware/riscv_dbltrp.c >>> @@ -0,0 +1,95 @@ >>> +// SPDX-License-Identifier: GPL-2.0-only >>> +/* >>> + * Copyright (C) 2023 Rivos Inc. >>> + */ >> >> nit: fix copyright year >>> + >>> +#define pr_fmt(fmt) "riscv-dbltrp: " fmt >>> + >>> +#include <linux/cpu.h> >>> +#include <linux/init.h> >>> +#include <linux/riscv_dbltrp.h> >>> +#include <linux/riscv_sse.h> >>> + >>> +#include <asm/sbi.h> >>> + >>> +static bool double_trap_enabled; >>> + >>> +static int riscv_sse_dbltrp_handle(uint32_t evt, void *arg, >>> + struct pt_regs *regs) >>> +{ >>> + __show_regs(regs); >>> + panic("Double trap !\n"); >>> + >>> + return 0; >> Curious: >> Does panic return? >> What's the point of returning from here? > >Hi Deepak, > >No, panic() does not return and indeed, the "return 0" is useless. It's >a leftover of a previous implementation without panic in order to keep >GCC mouth shut ;). > >> >>> +} >>> + >>> +struct cpu_dbltrp_data { >>> + int error; >>> +}; >>> + >>> +static void >>> +sbi_cpu_enable_double_trap(void *data) >>> +{ >>> + struct sbiret ret; >>> + struct cpu_dbltrp_data *cdd = data; >>> + >>> + ret = sbi_ecall(SBI_EXT_FWFT, SBI_EXT_FWFT_SET, >>> + SBI_FWFT_DOUBLE_TRAP_ENABLE, 1, 0, 0, 0, 0); >>> + >>> + if (ret.error) { >>> + cdd->error = 1; >>> + pr_err("Failed to enable double trap on cpu %d\n", >>> smp_processor_id()); >>> + } >>> +} >>> + >>> +static int sbi_enable_double_trap(void) >>> +{ >>> + struct cpu_dbltrp_data cdd = {0}; >>> + >>> + on_each_cpu(sbi_cpu_enable_double_trap, &cdd, 1); >>> + if (cdd.error) >>> + return -1; >> >> There is a bug here. If `sbi_cpu_enable_double_trap` failed on all cpus >> but last cpu. >> Then cdd.error would not record error and will be reflect as if double >> trap was enabled. > >cdd.error is only written in case of error by the per-cpu callbacks, so >it is only set if enabled failed. Is there something I'm missing ? No. Sorry I missed that detail. lgtm. > >Thanks, > >Clément > >> >> Its less likely to happen that FW would return success for one cpu and >> fail for others. >> But there is non-zero probablity here. >> >
diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h index 744aa1796c92..9cd4ca66487c 100644 --- a/arch/riscv/include/asm/sbi.h +++ b/arch/riscv/include/asm/sbi.h @@ -314,6 +314,7 @@ enum sbi_sse_attr_id { #define SBI_SSE_ATTR_INTERRUPTED_FLAGS_SPIE (1 << 2) #define SBI_SSE_EVENT_LOCAL_RAS 0x00000000 +#define SBI_SSE_EVENT_LOCAL_DOUBLE_TRAP 0x00000001 #define SBI_SSE_EVENT_GLOBAL_RAS 0x00008000 #define SBI_SSE_EVENT_LOCAL_PMU 0x00010000 #define SBI_SSE_EVENT_LOCAL_SOFTWARE 0xffff0000 diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig index 59f611288807..a037f6e89942 100644 --- a/drivers/firmware/Kconfig +++ b/drivers/firmware/Kconfig @@ -197,6 +197,13 @@ config RISCV_SSE_TEST Select if you want to enable SSE extension testing at boot time. This will run a series of test which verifies SSE sanity. +config RISCV_DBLTRP + bool "Enable Double trap handling" + depends on RISCV_SSE && RISCV_SBI + default n + help + Select if you want to enable SSE double trap handler. + config SYSFB bool select BOOT_VESA_SUPPORT diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile index fb7b0c08c56d..ad67a1738c0f 100644 --- a/drivers/firmware/Makefile +++ b/drivers/firmware/Makefile @@ -18,6 +18,7 @@ obj-$(CONFIG_RASPBERRYPI_FIRMWARE) += raspberrypi.o obj-$(CONFIG_FW_CFG_SYSFS) += qemu_fw_cfg.o obj-$(CONFIG_RISCV_SSE) += riscv_sse.o obj-$(CONFIG_RISCV_SSE_TEST) += riscv_sse_test.o +obj-$(CONFIG_RISCV_DBLTRP) += riscv_dbltrp.o obj-$(CONFIG_SYSFB) += sysfb.o obj-$(CONFIG_SYSFB_SIMPLEFB) += sysfb_simplefb.o obj-$(CONFIG_TI_SCI_PROTOCOL) += ti_sci.o diff --git a/drivers/firmware/riscv_dbltrp.c b/drivers/firmware/riscv_dbltrp.c new file mode 100644 index 000000000000..72f9a067e87a --- /dev/null +++ b/drivers/firmware/riscv_dbltrp.c @@ -0,0 +1,95 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2023 Rivos Inc. + */ + +#define pr_fmt(fmt) "riscv-dbltrp: " fmt + +#include <linux/cpu.h> +#include <linux/init.h> +#include <linux/riscv_dbltrp.h> +#include <linux/riscv_sse.h> + +#include <asm/sbi.h> + +static bool double_trap_enabled; + +static int riscv_sse_dbltrp_handle(uint32_t evt, void *arg, + struct pt_regs *regs) +{ + __show_regs(regs); + panic("Double trap !\n"); + + return 0; +} + +struct cpu_dbltrp_data { + int error; +}; + +static void +sbi_cpu_enable_double_trap(void *data) +{ + struct sbiret ret; + struct cpu_dbltrp_data *cdd = data; + + ret = sbi_ecall(SBI_EXT_FWFT, SBI_EXT_FWFT_SET, + SBI_FWFT_DOUBLE_TRAP_ENABLE, 1, 0, 0, 0, 0); + + if (ret.error) { + cdd->error = 1; + pr_err("Failed to enable double trap on cpu %d\n", smp_processor_id()); + } +} + +static int sbi_enable_double_trap(void) +{ + struct cpu_dbltrp_data cdd = {0}; + + on_each_cpu(sbi_cpu_enable_double_trap, &cdd, 1); + if (cdd.error) + return -1; + + double_trap_enabled = true; + + return 0; +} + +bool riscv_double_trap_enabled(void) +{ + return double_trap_enabled; +} +EXPORT_SYMBOL(riscv_double_trap_enabled); + +static int __init riscv_dbltrp(void) +{ + struct sse_event *evt; + + if (!riscv_has_extension_unlikely(RISCV_ISA_EXT_SSDBLTRP)) { + pr_err("Ssdbltrp extension not available\n"); + return 1; + } + + if (!sbi_probe_extension(SBI_EXT_FWFT)) { + pr_err("Can not enable double trap, SBI_EXT_FWFT is not available\n"); + return 1; + } + + if (sbi_enable_double_trap()) { + pr_err("Failed to enable double trap on all cpus\n"); + return 1; + } + + evt = sse_event_register(SBI_SSE_EVENT_LOCAL_DOUBLE_TRAP, 0, + riscv_sse_dbltrp_handle, NULL); + if (IS_ERR(evt)) { + pr_err("SSE double trap register failed\n"); + return PTR_ERR(evt); + } + + sse_event_enable(evt); + pr_info("Double trap handling registered\n"); + + return 0; +} +device_initcall(riscv_dbltrp); diff --git a/include/linux/riscv_dbltrp.h b/include/linux/riscv_dbltrp.h new file mode 100644 index 000000000000..6de4f43fae6b --- /dev/null +++ b/include/linux/riscv_dbltrp.h @@ -0,0 +1,19 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2023 Rivos Inc. + */ + +#ifndef __LINUX_RISCV_DBLTRP_H +#define __LINUX_RISCV_DBLTRP_H + +#if defined(CONFIG_RISCV_DBLTRP) +bool riscv_double_trap_enabled(void); +#else + +static inline bool riscv_double_trap_enabled(void) +{ + return false; +} +#endif + +#endif /* __LINUX_RISCV_DBLTRP_H */
Add a small driver to request double trap enabling as well as registering a SSE handler for double trap. This will also be used by KVM SBI FWFT extension support to detect if it is possible to enable double trap in VS-mode. Signed-off-by: Clément Léger <cleger@rivosinc.com> --- arch/riscv/include/asm/sbi.h | 1 + drivers/firmware/Kconfig | 7 +++ drivers/firmware/Makefile | 1 + drivers/firmware/riscv_dbltrp.c | 95 +++++++++++++++++++++++++++++++++ include/linux/riscv_dbltrp.h | 19 +++++++ 5 files changed, 123 insertions(+) create mode 100644 drivers/firmware/riscv_dbltrp.c create mode 100644 include/linux/riscv_dbltrp.h