From d6d55f0b9d900673548515614b56ab55aa2c51f8 Mon Sep 17 00:00:00 2001 From: Jacob Shin Date: Thu, 29 May 2014 17:26:50 +0200 Subject: perf/x86/amd: AMD support for bp_len > HW_BREAKPOINT_LEN_8 Implement hardware breakpoint address mask for AMD Family 16h and above processors. CPUID feature bit indicates hardware support for DRn_ADDR_MASK MSRs. These masks further qualify DRn/DR7 hardware breakpoint addresses to allow matching of larger addresses ranges. Valuable advice and pseudo code from Oleg Nesterov Signed-off-by: Jacob Shin Signed-off-by: Suravee Suthikulpanit Acked-by: Jiri Olsa Reviewed-by: Oleg Nesterov Cc: Arnaldo Carvalho de Melo Cc: Ingo Molnar Cc: Namhyung Kim Cc: Peter Zijlstra Cc: xiakaixu Signed-off-by: Frederic Weisbecker --- arch/x86/kernel/cpu/amd.c | 19 +++++++++++++++++++ arch/x86/kernel/hw_breakpoint.c | 20 ++++++++++++++++---- 2 files changed, 35 insertions(+), 4 deletions(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 813d29d00a17..abe4ec760db3 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -870,3 +870,22 @@ static bool cpu_has_amd_erratum(struct cpuinfo_x86 *cpu, const int *erratum) return false; } + +void set_dr_addr_mask(unsigned long 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 3d5fb509bdeb..b5cb0c59ea87 100644 --- a/arch/x86/kernel/hw_breakpoint.c +++ b/arch/x86/kernel/hw_breakpoint.c @@ -126,6 +126,8 @@ int arch_install_hw_breakpoint(struct perf_event *bp) *dr7 |= encode_dr7(i, info->len, info->type); set_debugreg(*dr7, 7); + if (info->mask) + set_dr_addr_mask(info->mask, i); return 0; } @@ -161,6 +163,8 @@ void arch_uninstall_hw_breakpoint(struct perf_event *bp) *dr7 &= ~__encode_dr7(i, info->len, info->type); set_debugreg(*dr7, 7); + if (info->mask) + set_dr_addr_mask(0, i); } static int get_hbp_len(u8 hbp_len) @@ -277,6 +281,8 @@ static int arch_build_bp_info(struct perf_event *bp) } /* Len */ + info->mask = 0; + switch (bp->attr.bp_len) { case HW_BREAKPOINT_LEN_1: info->len = X86_BREAKPOINT_LEN_1; @@ -293,11 +299,17 @@ static int arch_build_bp_info(struct perf_event *bp) break; #endif default: - return -EINVAL; + if (!is_power_of_2(bp->attr.bp_len)) + return -EINVAL; + if (!cpu_has_bpext) + return -EOPNOTSUPP; + info->mask = bp->attr.bp_len - 1; + info->len = X86_BREAKPOINT_LEN_1; } return 0; } + /* * Validate the arch-specific HW Breakpoint register settings */ @@ -312,11 +324,11 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp) if (ret) return ret; - ret = -EINVAL; - switch (info->len) { case X86_BREAKPOINT_LEN_1: align = 0; + if (info->mask) + align = info->mask; break; case X86_BREAKPOINT_LEN_2: align = 1; @@ -330,7 +342,7 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp) break; #endif default: - return ret; + WARN_ON_ONCE(1); } /* -- cgit v1.2.3 From 36748b9518a2437beffe861b47dff6d12b736b3f Mon Sep 17 00:00:00 2001 From: Jacob Shin Date: Thu, 29 May 2014 17:26:53 +0200 Subject: perf/x86: Remove get_hbp_len and replace with bp_len Clean up the logic for determining the breakpoint length Signed-off-by: Jacob Shin Signed-off-by: Suravee Suthikulpanit Acked-by: Jiri Olsa Reviewed-by: Oleg Nesterov Cc: Arnaldo Carvalho de Melo Cc: Ingo Molnar Cc: Namhyung Kim Cc: Peter Zijlstra Cc: xiakaixu Signed-off-by: Frederic Weisbecker --- arch/x86/kernel/hw_breakpoint.c | 25 +------------------------ 1 file changed, 1 insertion(+), 24 deletions(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoint.c index b5cb0c59ea87..7114ba220fd4 100644 --- a/arch/x86/kernel/hw_breakpoint.c +++ b/arch/x86/kernel/hw_breakpoint.c @@ -167,29 +167,6 @@ void arch_uninstall_hw_breakpoint(struct perf_event *bp) set_dr_addr_mask(0, i); } -static int get_hbp_len(u8 hbp_len) -{ - unsigned int len_in_bytes = 0; - - switch (hbp_len) { - case X86_BREAKPOINT_LEN_1: - len_in_bytes = 1; - break; - case X86_BREAKPOINT_LEN_2: - len_in_bytes = 2; - break; - case X86_BREAKPOINT_LEN_4: - len_in_bytes = 4; - break; -#ifdef CONFIG_X86_64 - case X86_BREAKPOINT_LEN_8: - len_in_bytes = 8; - break; -#endif - } - return len_in_bytes; -} - /* * Check for virtual address in kernel space. */ @@ -200,7 +177,7 @@ int arch_check_bp_in_kernelspace(struct perf_event *bp) struct arch_hw_breakpoint *info = counter_arch_bp(bp); va = info->address; - len = get_hbp_len(info->len); + len = bp->attr.bp_len; return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE); } -- cgit v1.2.3