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-rw-r--r--arch/x86/kernel/perf_regs.c202
1 files changed, 202 insertions, 0 deletions
diff --git a/arch/x86/kernel/perf_regs.c b/arch/x86/kernel/perf_regs.c
new file mode 100644
index 000000000..624703af8
--- /dev/null
+++ b/arch/x86/kernel/perf_regs.c
@@ -0,0 +1,202 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/sched/task_stack.h>
+#include <linux/perf_event.h>
+#include <linux/bug.h>
+#include <linux/stddef.h>
+#include <asm/perf_regs.h>
+#include <asm/ptrace.h>
+
+#ifdef CONFIG_X86_32
+#define PERF_REG_X86_MAX PERF_REG_X86_32_MAX
+#else
+#define PERF_REG_X86_MAX PERF_REG_X86_64_MAX
+#endif
+
+#define PT_REGS_OFFSET(id, r) [id] = offsetof(struct pt_regs, r)
+
+static unsigned int pt_regs_offset[PERF_REG_X86_MAX] = {
+ PT_REGS_OFFSET(PERF_REG_X86_AX, ax),
+ PT_REGS_OFFSET(PERF_REG_X86_BX, bx),
+ PT_REGS_OFFSET(PERF_REG_X86_CX, cx),
+ PT_REGS_OFFSET(PERF_REG_X86_DX, dx),
+ PT_REGS_OFFSET(PERF_REG_X86_SI, si),
+ PT_REGS_OFFSET(PERF_REG_X86_DI, di),
+ PT_REGS_OFFSET(PERF_REG_X86_BP, bp),
+ PT_REGS_OFFSET(PERF_REG_X86_SP, sp),
+ PT_REGS_OFFSET(PERF_REG_X86_IP, ip),
+ PT_REGS_OFFSET(PERF_REG_X86_FLAGS, flags),
+ PT_REGS_OFFSET(PERF_REG_X86_CS, cs),
+ PT_REGS_OFFSET(PERF_REG_X86_SS, ss),
+#ifdef CONFIG_X86_32
+ PT_REGS_OFFSET(PERF_REG_X86_DS, ds),
+ PT_REGS_OFFSET(PERF_REG_X86_ES, es),
+ PT_REGS_OFFSET(PERF_REG_X86_FS, fs),
+ PT_REGS_OFFSET(PERF_REG_X86_GS, gs),
+#else
+ /*
+ * The pt_regs struct does not store
+ * ds, es, fs, gs in 64 bit mode.
+ */
+ (unsigned int) -1,
+ (unsigned int) -1,
+ (unsigned int) -1,
+ (unsigned int) -1,
+#endif
+#ifdef CONFIG_X86_64
+ PT_REGS_OFFSET(PERF_REG_X86_R8, r8),
+ PT_REGS_OFFSET(PERF_REG_X86_R9, r9),
+ PT_REGS_OFFSET(PERF_REG_X86_R10, r10),
+ PT_REGS_OFFSET(PERF_REG_X86_R11, r11),
+ PT_REGS_OFFSET(PERF_REG_X86_R12, r12),
+ PT_REGS_OFFSET(PERF_REG_X86_R13, r13),
+ PT_REGS_OFFSET(PERF_REG_X86_R14, r14),
+ PT_REGS_OFFSET(PERF_REG_X86_R15, r15),
+#endif
+};
+
+u64 perf_reg_value(struct pt_regs *regs, int idx)
+{
+ struct x86_perf_regs *perf_regs;
+
+ if (idx >= PERF_REG_X86_XMM0 && idx < PERF_REG_X86_XMM_MAX) {
+ perf_regs = container_of(regs, struct x86_perf_regs, regs);
+ if (!perf_regs->xmm_regs)
+ return 0;
+ return perf_regs->xmm_regs[idx - PERF_REG_X86_XMM0];
+ }
+
+ if (WARN_ON_ONCE(idx >= ARRAY_SIZE(pt_regs_offset)))
+ return 0;
+
+ return regs_get_register(regs, pt_regs_offset[idx]);
+}
+
+#define PERF_REG_X86_RESERVED (((1ULL << PERF_REG_X86_XMM0) - 1) & \
+ ~((1ULL << PERF_REG_X86_MAX) - 1))
+
+#ifdef CONFIG_X86_32
+#define REG_NOSUPPORT ((1ULL << PERF_REG_X86_R8) | \
+ (1ULL << PERF_REG_X86_R9) | \
+ (1ULL << PERF_REG_X86_R10) | \
+ (1ULL << PERF_REG_X86_R11) | \
+ (1ULL << PERF_REG_X86_R12) | \
+ (1ULL << PERF_REG_X86_R13) | \
+ (1ULL << PERF_REG_X86_R14) | \
+ (1ULL << PERF_REG_X86_R15))
+
+int perf_reg_validate(u64 mask)
+{
+ if (!mask || (mask & (REG_NOSUPPORT | PERF_REG_X86_RESERVED)))
+ return -EINVAL;
+
+ return 0;
+}
+
+u64 perf_reg_abi(struct task_struct *task)
+{
+ return PERF_SAMPLE_REGS_ABI_32;
+}
+
+void perf_get_regs_user(struct perf_regs *regs_user,
+ struct pt_regs *regs)
+{
+ regs_user->regs = task_pt_regs(current);
+ regs_user->abi = perf_reg_abi(current);
+}
+#else /* CONFIG_X86_64 */
+#define REG_NOSUPPORT ((1ULL << PERF_REG_X86_DS) | \
+ (1ULL << PERF_REG_X86_ES) | \
+ (1ULL << PERF_REG_X86_FS) | \
+ (1ULL << PERF_REG_X86_GS))
+
+int perf_reg_validate(u64 mask)
+{
+ if (!mask || (mask & (REG_NOSUPPORT | PERF_REG_X86_RESERVED)))
+ return -EINVAL;
+
+ return 0;
+}
+
+u64 perf_reg_abi(struct task_struct *task)
+{
+ if (!user_64bit_mode(task_pt_regs(task)))
+ return PERF_SAMPLE_REGS_ABI_32;
+ else
+ return PERF_SAMPLE_REGS_ABI_64;
+}
+
+static DEFINE_PER_CPU(struct pt_regs, nmi_user_regs);
+
+void perf_get_regs_user(struct perf_regs *regs_user,
+ struct pt_regs *regs)
+{
+ struct pt_regs *regs_user_copy = this_cpu_ptr(&nmi_user_regs);
+ struct pt_regs *user_regs = task_pt_regs(current);
+
+ if (!in_nmi()) {
+ regs_user->regs = user_regs;
+ regs_user->abi = perf_reg_abi(current);
+ return;
+ }
+
+ /*
+ * If we're in an NMI that interrupted task_pt_regs setup, then
+ * we can't sample user regs at all. This check isn't really
+ * sufficient, though, as we could be in an NMI inside an interrupt
+ * that happened during task_pt_regs setup.
+ */
+ if (regs->sp > (unsigned long)&user_regs->r11 &&
+ regs->sp <= (unsigned long)(user_regs + 1)) {
+ regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
+ regs_user->regs = NULL;
+ return;
+ }
+
+ /*
+ * These registers are always saved on 64-bit syscall entry.
+ * On 32-bit entry points, they are saved too except r8..r11.
+ */
+ regs_user_copy->ip = user_regs->ip;
+ regs_user_copy->ax = user_regs->ax;
+ regs_user_copy->cx = user_regs->cx;
+ regs_user_copy->dx = user_regs->dx;
+ regs_user_copy->si = user_regs->si;
+ regs_user_copy->di = user_regs->di;
+ regs_user_copy->r8 = user_regs->r8;
+ regs_user_copy->r9 = user_regs->r9;
+ regs_user_copy->r10 = user_regs->r10;
+ regs_user_copy->r11 = user_regs->r11;
+ regs_user_copy->orig_ax = user_regs->orig_ax;
+ regs_user_copy->flags = user_regs->flags;
+ regs_user_copy->sp = user_regs->sp;
+ regs_user_copy->cs = user_regs->cs;
+ regs_user_copy->ss = user_regs->ss;
+ /*
+ * Store user space frame-pointer value on sample
+ * to facilitate stack unwinding for cases when
+ * user space executable code has such support
+ * enabled at compile time:
+ */
+ regs_user_copy->bp = user_regs->bp;
+
+ regs_user_copy->bx = -1;
+ regs_user_copy->r12 = -1;
+ regs_user_copy->r13 = -1;
+ regs_user_copy->r14 = -1;
+ regs_user_copy->r15 = -1;
+ /*
+ * For this to be at all useful, we need a reasonable guess for
+ * the ABI. Be careful: we're in NMI context, and we're
+ * considering current to be the current task, so we should
+ * be careful not to look at any other percpu variables that might
+ * change during context switches.
+ */
+ regs_user->abi = user_64bit_mode(user_regs) ?
+ PERF_SAMPLE_REGS_ABI_64 : PERF_SAMPLE_REGS_ABI_32;
+
+ regs_user->regs = regs_user_copy;
+}
+#endif /* CONFIG_X86_32 */