@@ -72,7 +72,7 @@ static inline void dynamic_scs_init(void)
static inline void dynamic_scs_init(void) {}
#endif
-int scs_patch(const u8 eh_frame[], int size);
+int __pi_scs_patch(const u8 eh_frame[], int size);
#endif /* __ASSEMBLY __ */
@@ -72,8 +72,6 @@ obj-$(CONFIG_ARM64_PTR_AUTH) += pointer_auth.o
obj-$(CONFIG_ARM64_MTE) += mte.o
obj-y += vdso-wrap.o
obj-$(CONFIG_COMPAT_VDSO) += vdso32-wrap.o
-obj-$(CONFIG_UNWIND_PATCH_PAC_INTO_SCS) += patch-scs.o
-CFLAGS_patch-scs.o += -mbranch-protection=none
# Force dependency (vdso*-wrap.S includes vdso.so through incbin)
$(obj)/vdso-wrap.o: $(obj)/vdso/vdso.so
@@ -490,9 +490,6 @@ SYM_FUNC_START_LOCAL(__primary_switched)
#endif
#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
bl kasan_early_init
-#endif
-#ifdef CONFIG_UNWIND_PATCH_PAC_INTO_SCS
- bl scs_patch_vmlinux
#endif
mov x0, x20
bl finalise_el2 // Prefer VHE if possible
@@ -792,6 +789,11 @@ SYM_FUNC_START_LOCAL(__primary_switch)
#ifdef CONFIG_RELOCATABLE
mov x0, x23
bl __pi_relocate_kernel
+#endif
+#ifdef CONFIG_UNWIND_PATCH_PAC_INTO_SCS
+ ldr x0, =__eh_frame_start
+ ldr x1, =__eh_frame_end
+ bl __pi_scs_patch_vmlinux
#endif
ldr x8, =__primary_switched
adrp x0, KERNEL_START // __pa(KERNEL_START)
@@ -516,7 +516,7 @@ int module_finalize(const Elf_Ehdr *hdr,
if (scs_is_dynamic()) {
s = find_section(hdr, sechdrs, ".init.eh_frame");
if (s)
- scs_patch((void *)s->sh_addr, s->sh_size);
+ __pi_scs_patch((void *)s->sh_addr, s->sh_size);
}
return module_init_ftrace_plt(hdr, sechdrs, me);
@@ -38,7 +38,9 @@ $(obj)/lib-%.pi.o: OBJCOPYFLAGS += --prefix-alloc-sections=.init
$(obj)/lib-%.o: $(srctree)/lib/%.c FORCE
$(call if_changed_rule,cc_o_c)
-obj-y := idreg-override.pi.o lib-fdt.pi.o lib-fdt_ro.pi.o
-obj-$(CONFIG_RELOCATABLE) += relocate.pi.o
-obj-$(CONFIG_RANDOMIZE_BASE) += kaslr_early.pi.o
-extra-y := $(patsubst %.pi.o,%.o,$(obj-y))
+obj-y := idreg-override.pi.o \
+ lib-fdt.pi.o lib-fdt_ro.pi.o
+obj-$(CONFIG_RELOCATABLE) += relocate.pi.o
+obj-$(CONFIG_RANDOMIZE_BASE) += kaslr_early.pi.o
+obj-$(CONFIG_UNWIND_PATCH_PAC_INTO_SCS) += patch-scs.pi.o
+extra-y := $(patsubst %.pi.o,%.o,$(obj-y))
similarity index 91%
rename from arch/arm64/kernel/patch-scs.c
rename to arch/arm64/kernel/pi/patch-scs.c
@@ -4,14 +4,11 @@
* Author: Ard Biesheuvel <ardb@google.com>
*/
-#include <linux/bug.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/linkage.h>
-#include <linux/printk.h>
#include <linux/types.h>
-#include <asm/cacheflush.h>
#include <asm/scs.h>
//
@@ -81,7 +78,11 @@ static void __always_inline scs_patch_loc(u64 loc)
*/
return;
}
- dcache_clean_pou(loc, loc + sizeof(u32));
+ if (IS_ENABLED(CONFIG_ARM64_WORKAROUND_CLEAN_CACHE))
+ asm("dc civac, %0" :: "r"(loc));
+ else
+ asm(ALTERNATIVE("dc cvau, %0", "nop", ARM64_HAS_CACHE_IDC)
+ :: "r"(loc));
}
/*
@@ -128,10 +129,10 @@ struct eh_frame {
};
};
-static int noinstr scs_handle_fde_frame(const struct eh_frame *frame,
- bool fde_has_augmentation_data,
- int code_alignment_factor,
- bool dry_run)
+static int scs_handle_fde_frame(const struct eh_frame *frame,
+ bool fde_has_augmentation_data,
+ int code_alignment_factor,
+ bool dry_run)
{
int size = frame->size - offsetof(struct eh_frame, opcodes) + 4;
u64 loc = (u64)offset_to_ptr(&frame->initial_loc);
@@ -198,14 +199,13 @@ static int noinstr scs_handle_fde_frame(const struct eh_frame *frame,
break;
default:
- pr_err("unhandled opcode: %02x in FDE frame %lx\n", opcode[-1], (uintptr_t)frame);
return -ENOEXEC;
}
}
return 0;
}
-int noinstr scs_patch(const u8 eh_frame[], int size)
+int scs_patch(const u8 eh_frame[], int size)
{
const u8 *p = eh_frame;
@@ -251,12 +251,12 @@ int noinstr scs_patch(const u8 eh_frame[], int size)
return 0;
}
-asmlinkage void __init scs_patch_vmlinux(void)
+asmlinkage void __init scs_patch_vmlinux(const u8 start[], const u8 end[])
{
if (!should_patch_pac_into_scs())
return;
- WARN_ON(scs_patch(__eh_frame_start, __eh_frame_end - __eh_frame_start));
- icache_inval_all_pou();
+ scs_patch(start, end - start);
+ asm("ic ialluis");
isb();
}
Once we update the early kernel mapping code to only map the kernel once with the right permissions, we can no longer perform code patching via this mapping. So move this code to an earlier stage of the boot, right after applying the relocations. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> --- arch/arm64/include/asm/scs.h | 2 +- arch/arm64/kernel/Makefile | 2 -- arch/arm64/kernel/head.S | 8 +++--- arch/arm64/kernel/module.c | 2 +- arch/arm64/kernel/pi/Makefile | 10 +++++--- arch/arm64/kernel/{ => pi}/patch-scs.c | 26 ++++++++++---------- 6 files changed, 26 insertions(+), 24 deletions(-)