[PATCH V2 2/4] perf/x86/amd: AMD implementation for hardware breakpoint address mask
From: Jacob Shin
Date: Tue Apr 23 2013 - 03:58:16 EST
Implement hardware breakpoint address mask for AMD Family 16h (and
any other future) processors. CPUID feature bit indicates the hardware
support for DRn_ADDR_MASK MSRs.
Signed-off-by: Jacob Shin <jacob.shin@xxxxxxx>
---
arch/x86/include/asm/cpufeature.h | 2 ++
arch/x86/include/asm/debugreg.h | 5 +++++
arch/x86/include/asm/hw_breakpoint.h | 1 +
arch/x86/include/uapi/asm/msr-index.h | 6 ++++++
arch/x86/kernel/cpu/amd.c | 19 +++++++++++++++++++
arch/x86/kernel/hw_breakpoint.c | 16 ++++++++++++++++
6 files changed, 49 insertions(+)
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index ac10df7..bee6994 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -168,6 +168,7 @@
#define X86_FEATURE_TOPOEXT (6*32+22) /* topology extensions CPUID leafs */
#define X86_FEATURE_PERFCTR_CORE (6*32+23) /* core performance counter extensions */
#define X86_FEATURE_PERFCTR_NB (6*32+24) /* NB performance counter extensions */
+#define X86_FEATURE_BPEXT (6*32+26) /* data breakpoint extension */
#define X86_FEATURE_PERFCTR_L2 (6*32+28) /* L2 performance counter extensions */
/*
@@ -317,6 +318,7 @@ extern const char * const x86_power_flags[32];
#define cpu_has_cx16 boot_cpu_has(X86_FEATURE_CX16)
#define cpu_has_eager_fpu boot_cpu_has(X86_FEATURE_EAGER_FPU)
#define cpu_has_topoext boot_cpu_has(X86_FEATURE_TOPOEXT)
+#define cpu_has_bpext boot_cpu_has(X86_FEATURE_BPEXT)
#ifdef CONFIG_X86_64
diff --git a/arch/x86/include/asm/debugreg.h b/arch/x86/include/asm/debugreg.h
index 4b528a9..9b38750 100644
--- a/arch/x86/include/asm/debugreg.h
+++ b/arch/x86/include/asm/debugreg.h
@@ -114,5 +114,10 @@ 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(u32 mask, int dr);
+#else
+static inline void set_dr_addr_mask(u32 mask, int dr) { }
+#endif
#endif /* _ASM_X86_DEBUGREG_H */
diff --git a/arch/x86/include/asm/hw_breakpoint.h b/arch/x86/include/asm/hw_breakpoint.h
index ef1c4d2..c0b89d8 100644
--- a/arch/x86/include/asm/hw_breakpoint.h
+++ b/arch/x86/include/asm/hw_breakpoint.h
@@ -14,6 +14,7 @@ struct arch_hw_breakpoint {
unsigned long address;
u8 len;
u8 type;
+ u32 mask;
};
#include <linux/kdebug.h>
diff --git a/arch/x86/include/uapi/asm/msr-index.h b/arch/x86/include/uapi/asm/msr-index.h
index b575788..ea7c98f 100644
--- a/arch/x86/include/uapi/asm/msr-index.h
+++ b/arch/x86/include/uapi/asm/msr-index.h
@@ -200,6 +200,12 @@
#define MSR_F16H_L2I_PERF_CTL 0xc0010230
#define MSR_F16H_L2I_PERF_CTR 0xc0010231
+/* Fam 16h MSRs */
+#define MSR_F16H_DR0_ADDR_MASK 0xc0011027
+#define MSR_F16H_DR1_ADDR_MASK 0xc0011019
+#define MSR_F16H_DR2_ADDR_MASK 0xc001101a
+#define MSR_F16H_DR3_ADDR_MASK 0xc001101b
+
/* Fam 15h MSRs */
#define MSR_F15H_PERF_CTL 0xc0010200
#define MSR_F15H_PERF_CTR 0xc0010201
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index fa96eb0..aadc499 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -910,3 +910,22 @@ bool cpu_has_amd_erratum(const int *erratum)
}
EXPORT_SYMBOL_GPL(cpu_has_amd_erratum);
+
+void set_dr_addr_mask(u32 mask, int dr)
+{
+ if (!cpu_has_bpext)
+ return;
+
+ switch (dr) {
+ case 0:
+ wrmsr(MSR_F16H_DR0_ADDR_MASK, mask, 0);
+ break;
+ case 1:
+ case 2:
+ case 3:
+ wrmsr(MSR_F16H_DR1_ADDR_MASK - 1 + dr, mask, 0);
+ break;
+ default:
+ break;
+ }
+}
diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoint.c
index 02f0763..58a1b80 100644
--- a/arch/x86/kernel/hw_breakpoint.c
+++ b/arch/x86/kernel/hw_breakpoint.c
@@ -121,6 +121,8 @@ int arch_install_hw_breakpoint(struct perf_event *bp)
if (WARN_ONCE(i == HBP_NUM, "Can't find any breakpoint slot"))
return -EBUSY;
+ set_dr_addr_mask(info->mask, i);
+
set_debugreg(info->address, i);
__this_cpu_write(cpu_debugreg[i], info->address);
@@ -163,6 +165,8 @@ void arch_uninstall_hw_breakpoint(struct perf_event *bp)
*dr7 &= ~__encode_dr7(i, info->len, info->type);
set_debugreg(*dr7, 7);
+
+ set_dr_addr_mask(0, i);
}
static int get_hbp_len(u8 hbp_len)
@@ -254,6 +258,7 @@ static int arch_build_bp_info(struct perf_event *bp)
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
info->address = bp->attr.bp_addr;
+ info->mask = bp->attr.bp_addr_mask;
/* Type */
switch (bp->attr.bp_type) {
@@ -345,6 +350,17 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp)
return 0;
}
+int arch_validate_hwbkpt_addr_mask(struct perf_event *bp)
+{
+ if (!cpu_has_bpext)
+ return -EOPNOTSUPP;
+
+ if (bp->attr.bp_addr & bp->attr.bp_addr_mask)
+ return -EINVAL;
+
+ return 0;
+}
+
/*
* Dump the debug register contents to the user.
* We can't dump our per cpu values because it
--
1.7.9.5
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