| Message ID | 20210217120143.6106-2-joro@8bytes.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | x86/sev-es: Check for trusted regs->sp in __sev_es_ist_enter() | expand |
I guess subject prefix should be "x86/traps:" but I'll fix that up while applying eventually. On Wed, Feb 17, 2021 at 01:01:41PM +0100, Joerg Roedel wrote: > From: Joerg Roedel <jroedel@suse.de> > > Introduce a helper to check whether an exception came from the syscall > gap and use it in the SEV-ES code > > Fixes: 315562c9af3d5 ("x86/sev-es: Adjust #VC IST Stack on entering NMI handler") > Cc: stable@vger.kernel.org # 5.10+ > Signed-off-by: Joerg Roedel <jroedel@suse.de> > --- > arch/x86/include/asm/ptrace.h | 8 ++++++++ > arch/x86/kernel/traps.c | 3 +-- > 2 files changed, 9 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h > index d8324a236696..14854b2c4944 100644 > --- a/arch/x86/include/asm/ptrace.h > +++ b/arch/x86/include/asm/ptrace.h > @@ -94,6 +94,8 @@ struct pt_regs { > #include <asm/paravirt_types.h> > #endif > > +#include <asm/proto.h> > + > struct cpuinfo_x86; > struct task_struct; > > @@ -175,6 +177,12 @@ static inline bool any_64bit_mode(struct pt_regs *regs) > #ifdef CONFIG_X86_64 > #define current_user_stack_pointer() current_pt_regs()->sp > #define compat_user_stack_pointer() current_pt_regs()->sp > + > +static inline bool from_syscall_gap(struct pt_regs *regs) rip_within_syscall_gap() sounds kinda better to me and it is more readable when you look at it at the usage site: if (rip_within_syscall_gap(regs)) ...
diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h index d8324a236696..14854b2c4944 100644 --- a/arch/x86/include/asm/ptrace.h +++ b/arch/x86/include/asm/ptrace.h @@ -94,6 +94,8 @@ struct pt_regs { #include <asm/paravirt_types.h> #endif +#include <asm/proto.h> + struct cpuinfo_x86; struct task_struct; @@ -175,6 +177,12 @@ static inline bool any_64bit_mode(struct pt_regs *regs) #ifdef CONFIG_X86_64 #define current_user_stack_pointer() current_pt_regs()->sp #define compat_user_stack_pointer() current_pt_regs()->sp + +static inline bool from_syscall_gap(struct pt_regs *regs) +{ + return (regs->ip >= (unsigned long)entry_SYSCALL_64 && + regs->ip < (unsigned long)entry_SYSCALL_64_safe_stack); +} #endif static inline unsigned long kernel_stack_pointer(struct pt_regs *regs) diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 7f5aec758f0e..b4f2b4e9066d 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -694,8 +694,7 @@ asmlinkage __visible noinstr struct pt_regs *vc_switch_off_ist(struct pt_regs *r * In the SYSCALL entry path the RSP value comes from user-space - don't * trust it and switch to the current kernel stack */ - if (regs->ip >= (unsigned long)entry_SYSCALL_64 && - regs->ip < (unsigned long)entry_SYSCALL_64_safe_stack) { + if (from_syscall_gap(regs)) { sp = this_cpu_read(cpu_current_top_of_stack); goto sync; }