| Message ID | 20220309220939.392227-1-keescook@chromium.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | b847bd64ea9f484510e27065cb2bccc58d9b829b |
| Headers | show |
| Series | [v2] MIPS: Only use current_stack_pointer on GCC | expand |
From: Kees Cook > Sent: 09 March 2022 22:10 > > Unfortunately, Clang did not have support for "sp" as a global register > definition, and was crashing after the addition of current_stack_pointer. > This has been fixed in Clang 15, but earlier Clang versions need to ^^ 14 > avoid this code, so add a versioned test and revert back to the > open-coded asm instances. Fixes Clang build error: > > fatal error: error in backend: Invalid register name global variable David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
On Wed, Mar 9, 2022 at 2:44 PM David Laight <David.Laight@aculab.com> wrote: > > From: Kees Cook > > Sent: 09 March 2022 22:10 > > > > Unfortunately, Clang did not have support for "sp" as a global register > > definition, and was crashing after the addition of current_stack_pointer. > > This has been fixed in Clang 15, but earlier Clang versions need to > ^^ 14 Yeah, with that fixed: Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Once clang-14 is the minimally supported version, we can go back to removing the inline asm for everyone. > > avoid this code, so add a versioned test and revert back to the > > open-coded asm instances. Fixes Clang build error: > > > > fatal error: error in backend: Invalid register name global variable > > David > > - > Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK > Registration No: 1397386 (Wales) >
On Wed, Mar 09, 2022 at 02:09:39PM -0800, Kees Cook wrote: > Unfortunately, Clang did not have support for "sp" as a global register > definition, and was crashing after the addition of current_stack_pointer. > This has been fixed in Clang 15, but earlier Clang versions need to > avoid this code, so add a versioned test and revert back to the > open-coded asm instances. Fixes Clang build error: > > fatal error: error in backend: Invalid register name global variable > > Fixes: 200ed341b864 ("mips: Implement "current_stack_pointer"") > Reported-by: Nathan Chancellor <nathan@kernel.org> > Reviewed-by: Nathan Chancellor <nathan@kernel.org> > Link: https://lore.kernel.org/lkml/YikTQRql+il3HbrK@dev-arch.thelio-3990X > Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> > Cc: Marc Zyngier <maz@kernel.org> > Cc: Guenter Roeck <linux@roeck-us.net> > Cc: Yanteng Si <siyanteng01@gmail.com> > Cc: linux-mips@vger.kernel.org > Signed-off-by: Kees Cook <keescook@chromium.org> > --- > v1: https://lore.kernel.org/lkml/20220309204537.390428-1-keescook@chromium.org > v2: - adjust Clang version (Nathan) > --- > arch/mips/Kconfig | 2 +- > arch/mips/include/asm/thread_info.h | 2 ++ > arch/mips/kernel/irq.c | 3 ++- > arch/mips/lib/uncached.c | 4 +++- > 4 files changed, 8 insertions(+), 3 deletions(-) applied to mips-next with the Clang version in the decscription fixed. Thomas.
On Mon, Mar 14, 2022 at 03:52:15PM +0100, Thomas Bogendoerfer wrote: > On Wed, Mar 09, 2022 at 02:09:39PM -0800, Kees Cook wrote: > > Unfortunately, Clang did not have support for "sp" as a global register > > definition, and was crashing after the addition of current_stack_pointer. > > This has been fixed in Clang 15, but earlier Clang versions need to > > avoid this code, so add a versioned test and revert back to the > > open-coded asm instances. Fixes Clang build error: > > > > fatal error: error in backend: Invalid register name global variable > > > > Fixes: 200ed341b864 ("mips: Implement "current_stack_pointer"") > > Reported-by: Nathan Chancellor <nathan@kernel.org> > > Reviewed-by: Nathan Chancellor <nathan@kernel.org> > > Link: https://lore.kernel.org/lkml/YikTQRql+il3HbrK@dev-arch.thelio-3990X > > Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> > > Cc: Marc Zyngier <maz@kernel.org> > > Cc: Guenter Roeck <linux@roeck-us.net> > > Cc: Yanteng Si <siyanteng01@gmail.com> > > Cc: linux-mips@vger.kernel.org > > Signed-off-by: Kees Cook <keescook@chromium.org> > > --- > > v1: https://lore.kernel.org/lkml/20220309204537.390428-1-keescook@chromium.org > > v2: - adjust Clang version (Nathan) > > --- > > arch/mips/Kconfig | 2 +- > > arch/mips/include/asm/thread_info.h | 2 ++ > > arch/mips/kernel/irq.c | 3 ++- > > arch/mips/lib/uncached.c | 4 +++- > > 4 files changed, 8 insertions(+), 3 deletions(-) > > applied to mips-next with the Clang version in the decscription fixed. Excellent; thanks very much! -Kees
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index 3f58b45fc953..0dae5f1e61cc 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -4,7 +4,7 @@ config MIPS default y select ARCH_32BIT_OFF_T if !64BIT select ARCH_BINFMT_ELF_STATE if MIPS_FP_SUPPORT - select ARCH_HAS_CURRENT_STACK_POINTER + select ARCH_HAS_CURRENT_STACK_POINTER if !CC_IS_CLANG || CLANG_VERSION >= 140000 select ARCH_HAS_DEBUG_VIRTUAL if !64BIT select ARCH_HAS_FORTIFY_SOURCE select ARCH_HAS_KCOV diff --git a/arch/mips/include/asm/thread_info.h b/arch/mips/include/asm/thread_info.h index 4463348d2372..ecae7470faa4 100644 --- a/arch/mips/include/asm/thread_info.h +++ b/arch/mips/include/asm/thread_info.h @@ -69,7 +69,9 @@ static inline struct thread_info *current_thread_info(void) return __current_thread_info; } +#ifdef CONFIG_ARCH_HAS_CURRENT_STACK_POINTER register unsigned long current_stack_pointer __asm__("sp"); +#endif #endif /* !__ASSEMBLY__ */ diff --git a/arch/mips/kernel/irq.c b/arch/mips/kernel/irq.c index fc313c49a417..5e11582fe308 100644 --- a/arch/mips/kernel/irq.c +++ b/arch/mips/kernel/irq.c @@ -75,8 +75,9 @@ void __init init_IRQ(void) #ifdef CONFIG_DEBUG_STACKOVERFLOW static inline void check_stack_overflow(void) { - unsigned long sp = current_stack_pointer; + unsigned long sp; + __asm__ __volatile__("move %0, $sp" : "=r" (sp)); sp &= THREAD_MASK; /* diff --git a/arch/mips/lib/uncached.c b/arch/mips/lib/uncached.c index f8d4ca046c3e..f80a67c092b6 100644 --- a/arch/mips/lib/uncached.c +++ b/arch/mips/lib/uncached.c @@ -40,7 +40,9 @@ unsigned long run_uncached(void *func) register long ret __asm__("$2"); long lfunc = (long)func, ufunc; long usp; - long sp = current_stack_pointer; + long sp; + + __asm__("move %0, $sp" : "=r" (sp)); if (sp >= (long)CKSEG0 && sp < (long)CKSEG2) usp = CKSEG1ADDR(sp);
Unfortunately, Clang did not have support for "sp" as a global register definition, and was crashing after the addition of current_stack_pointer. This has been fixed in Clang 15, but earlier Clang versions need to avoid this code, so add a versioned test and revert back to the open-coded asm instances. Fixes Clang build error: fatal error: error in backend: Invalid register name global variable Fixes: 200ed341b864 ("mips: Implement "current_stack_pointer"") Reported-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Link: https://lore.kernel.org/lkml/YikTQRql+il3HbrK@dev-arch.thelio-3990X Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Marc Zyngier <maz@kernel.org> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Yanteng Si <siyanteng01@gmail.com> Cc: linux-mips@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> --- v1: https://lore.kernel.org/lkml/20220309204537.390428-1-keescook@chromium.org v2: - adjust Clang version (Nathan) --- arch/mips/Kconfig | 2 +- arch/mips/include/asm/thread_info.h | 2 ++ arch/mips/kernel/irq.c | 3 ++- arch/mips/lib/uncached.c | 4 +++- 4 files changed, 8 insertions(+), 3 deletions(-)