diff options
| author | Jakub Kicinski <kuba@kernel.org> | 2023-02-09 12:05:25 -0800 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2023-02-09 12:25:40 -0800 |
| commit | 8697a258ae24703267d2a37d91ab757c91ef027e (patch) | |
| tree | 7a1798898ac64c72e6cf77d2320f036c963a16c1 /arch/x86/include | |
| parent | 0b34d68049b09821499b93d50b5a9d7d2ca449f6 (diff) | |
| parent | 35674e787518768626d3a0ffce1c13a7eeed922d (diff) | |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
net/devlink/leftover.c / net/core/devlink.c:
565b4824c39f ("devlink: change port event netdev notifier from per-net to global")
f05bd8ebeb69 ("devlink: move code to a dedicated directory")
687125b5799c ("devlink: split out core code")
https://lore.kernel.org/all/20230208094657.379f2b1a@canb.auug.org.au/
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'arch/x86/include')
| -rw-r--r-- | arch/x86/include/asm/debugreg.h | 26 |
1 files changed, 24 insertions, 2 deletions
diff --git a/arch/x86/include/asm/debugreg.h b/arch/x86/include/asm/debugreg.h index b049d950612f..ca97442e8d49 100644 --- a/arch/x86/include/asm/debugreg.h +++ b/arch/x86/include/asm/debugreg.h @@ -39,7 +39,20 @@ static __always_inline unsigned long native_get_debugreg(int regno) asm("mov %%db6, %0" :"=r" (val)); break; case 7: - asm("mov %%db7, %0" :"=r" (val)); + /* + * Apply __FORCE_ORDER to DR7 reads to forbid re-ordering them + * with other code. + * + * This is needed because a DR7 access can cause a #VC exception + * when running under SEV-ES. Taking a #VC exception is not a + * safe thing to do just anywhere in the entry code and + * re-ordering might place the access into an unsafe location. + * + * This happened in the NMI handler, where the DR7 read was + * re-ordered to happen before the call to sev_es_ist_enter(), + * causing stack recursion. + */ + asm volatile("mov %%db7, %0" : "=r" (val) : __FORCE_ORDER); break; default: BUG(); @@ -66,7 +79,16 @@ static __always_inline void native_set_debugreg(int regno, unsigned long value) asm("mov %0, %%db6" ::"r" (value)); break; case 7: - asm("mov %0, %%db7" ::"r" (value)); + /* + * Apply __FORCE_ORDER to DR7 writes to forbid re-ordering them + * with other code. + * + * While is didn't happen with a DR7 write (see the DR7 read + * comment above which explains where it happened), add the + * __FORCE_ORDER here too to avoid similar problems in the + * future. + */ + asm volatile("mov %0, %%db7" ::"r" (value), __FORCE_ORDER); break; default: BUG(); |