diff options
Diffstat (limited to 'arch/x86/include/asm/debugreg.h')
| -rw-r--r-- | arch/x86/include/asm/debugreg.h | 35 |
1 files changed, 23 insertions, 12 deletions
diff --git a/arch/x86/include/asm/debugreg.h b/arch/x86/include/asm/debugreg.h index fdbbbfec745a..a2c1f2d24b64 100644 --- a/arch/x86/include/asm/debugreg.h +++ b/arch/x86/include/asm/debugreg.h @@ -9,6 +9,14 @@ #include <asm/cpufeature.h> #include <asm/msr.h> +/* + * Define bits that are always set to 1 in DR7, only bit 10 is + * architecturally reserved to '1'. + * + * This is also the init/reset value for DR7. + */ +#define DR7_FIXED_1 0x00000400 + DECLARE_PER_CPU(unsigned long, cpu_dr7); #ifndef CONFIG_PARAVIRT_XXL @@ -23,7 +31,7 @@ DECLARE_PER_CPU(unsigned long, cpu_dr7); static __always_inline unsigned long native_get_debugreg(int regno) { - unsigned long val = 0; /* Damn you, gcc! */ + unsigned long val; switch (regno) { case 0: @@ -43,7 +51,7 @@ static __always_inline unsigned long native_get_debugreg(int regno) break; case 7: /* - * Apply __FORCE_ORDER to DR7 reads to forbid re-ordering them + * Use "asm volatile" for DR7 reads to forbid re-ordering them * with other code. * * This is needed because a DR7 access can cause a #VC exception @@ -55,7 +63,7 @@ static __always_inline unsigned long native_get_debugreg(int regno) * re-ordered to happen before the call to sev_es_ist_enter(), * causing stack recursion. */ - asm volatile("mov %%db7, %0" : "=r" (val) : __FORCE_ORDER); + asm volatile("mov %%db7, %0" : "=r" (val)); break; default: BUG(); @@ -83,15 +91,15 @@ static __always_inline void native_set_debugreg(int regno, unsigned long value) break; case 7: /* - * Apply __FORCE_ORDER to DR7 writes to forbid re-ordering them + * Use "asm volatile" for 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 + * "asm volatile" here too to avoid similar problems in the * future. */ - asm volatile("mov %0, %%db7" ::"r" (value), __FORCE_ORDER); + asm volatile("mov %0, %%db7" ::"r" (value)); break; default: BUG(); @@ -100,8 +108,8 @@ static __always_inline void native_set_debugreg(int regno, unsigned long value) static inline void hw_breakpoint_disable(void) { - /* Zero the control register for HW Breakpoint */ - set_debugreg(0UL, 7); + /* Reset the control register for HW Breakpoint */ + set_debugreg(DR7_FIXED_1, 7); /* Zero-out the individual HW breakpoint address registers */ set_debugreg(0UL, 0); @@ -125,9 +133,12 @@ static __always_inline unsigned long local_db_save(void) return 0; get_debugreg(dr7, 7); - dr7 &= ~0x400; /* architecturally set bit */ + + /* Architecturally set bit */ + dr7 &= ~DR7_FIXED_1; if (dr7) - set_debugreg(0, 7); + set_debugreg(DR7_FIXED_1, 7); + /* * Ensure the compiler doesn't lower the above statements into * the critical section; disabling breakpoints late would not @@ -169,7 +180,7 @@ static inline unsigned long get_debugctlmsr(void) if (boot_cpu_data.x86 < 6) return 0; #endif - rdmsrl(MSR_IA32_DEBUGCTLMSR, debugctlmsr); + rdmsrq(MSR_IA32_DEBUGCTLMSR, debugctlmsr); return debugctlmsr; } @@ -180,7 +191,7 @@ static inline void update_debugctlmsr(unsigned long debugctlmsr) if (boot_cpu_data.x86 < 6) return; #endif - wrmsrl(MSR_IA32_DEBUGCTLMSR, debugctlmsr); + wrmsrq(MSR_IA32_DEBUGCTLMSR, debugctlmsr); } #endif /* _ASM_X86_DEBUGREG_H */ |