From 37f49e37ab4cb5d0bc4c60eb5c6d4dd57db767bb Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Fri, 10 May 2024 07:44:59 +0000
Subject: [PATCH] gmac get mac form eeprom
---
kernel/arch/x86/include/asm/debugreg.h | 80 ++++++++++++++++++++++++++++------------
1 files changed, 56 insertions(+), 24 deletions(-)
diff --git a/kernel/arch/x86/include/asm/debugreg.h b/kernel/arch/x86/include/asm/debugreg.h
index 4505ac2..9ed8343 100644
--- a/kernel/arch/x86/include/asm/debugreg.h
+++ b/kernel/arch/x86/include/asm/debugreg.h
@@ -8,7 +8,7 @@
DECLARE_PER_CPU(unsigned long, cpu_dr7);
-#ifndef CONFIG_PARAVIRT
+#ifndef CONFIG_PARAVIRT_XXL
/*
* These special macros can be used to get or set a debugging register
*/
@@ -18,7 +18,7 @@
native_set_debugreg(register, value)
#endif
-static inline unsigned long native_get_debugreg(int regno)
+static __always_inline unsigned long native_get_debugreg(int regno)
{
unsigned long val = 0; /* Damn you, gcc! */
@@ -39,7 +39,20 @@
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();
@@ -47,7 +60,7 @@
return val;
}
-static inline void native_set_debugreg(int regno, unsigned long value)
+static __always_inline void native_set_debugreg(int regno, unsigned long value)
{
switch (regno) {
case 0:
@@ -66,7 +79,16 @@
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();
@@ -85,35 +107,45 @@
set_debugreg(0UL, 3);
}
-static inline int hw_breakpoint_active(void)
+static __always_inline bool hw_breakpoint_active(void)
{
return __this_cpu_read(cpu_dr7) & DR_GLOBAL_ENABLE_MASK;
}
-extern void aout_dump_debugregs(struct user *dump);
-
extern void hw_breakpoint_restore(void);
-#ifdef CONFIG_X86_64
-DECLARE_PER_CPU(int, debug_stack_usage);
-static inline void debug_stack_usage_inc(void)
+static __always_inline unsigned long local_db_save(void)
{
- __this_cpu_inc(debug_stack_usage);
+ unsigned long dr7;
+
+ if (static_cpu_has(X86_FEATURE_HYPERVISOR) && !hw_breakpoint_active())
+ return 0;
+
+ get_debugreg(dr7, 7);
+ dr7 &= ~0x400; /* architecturally set bit */
+ if (dr7)
+ set_debugreg(0, 7);
+ /*
+ * Ensure the compiler doesn't lower the above statements into
+ * the critical section; disabling breakpoints late would not
+ * be good.
+ */
+ barrier();
+
+ return dr7;
}
-static inline void debug_stack_usage_dec(void)
+
+static __always_inline void local_db_restore(unsigned long dr7)
{
- __this_cpu_dec(debug_stack_usage);
+ /*
+ * Ensure the compiler doesn't raise this statement into
+ * the critical section; enabling breakpoints early would
+ * not be good.
+ */
+ barrier();
+ if (dr7)
+ set_debugreg(dr7, 7);
}
-int is_debug_stack(unsigned long addr);
-void debug_stack_set_zero(void);
-void debug_stack_reset(void);
-#else /* !X86_64 */
-static inline int is_debug_stack(unsigned long addr) { return 0; }
-static inline void debug_stack_set_zero(void) { }
-static inline void debug_stack_reset(void) { }
-static inline void debug_stack_usage_inc(void) { }
-static inline void debug_stack_usage_dec(void) { }
-#endif /* X86_64 */
#ifdef CONFIG_CPU_SUP_AMD
extern void set_dr_addr_mask(unsigned long mask, int dr);
--
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