ARM64: perf: add support for perf registers API

This patch implements the functions required for the perf registers API,
allowing the perf tool to interface kernel register dumps with libunwind
in order to provide userspace backtracing.
Compat mode is also supported.

Only the general purpose user space registers are exported, i.e.:
 PERF_REG_ARM_X0,
 ...
 PERF_REG_ARM_X28,
 PERF_REG_ARM_FP,
 PERF_REG_ARM_LR,
 PERF_REG_ARM_SP,
 PERF_REG_ARM_PC
and not the PERF_REG_ARM_V* registers.

Signed-off-by: Jean Pihet <jean.pihet@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
(cherry picked from commit 2ee0d7fd36a3f87bc5b29b1ec54ad6728deedb41)
Signed-off-by: Mark Brown <broonie@linaro.org>
Conflicts:
	arch/arm64/kernel/Makefile

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 56b3f6d447ae10b8d53f9cfb767826fe90a97c11..a11651758cc4b8f985508c8f218a2b9de7e74a14 100644 (file)
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -26,6 +26,8 @@ config ARM64
        select HAVE_HW_BREAKPOINT if PERF_EVENTS
        select HAVE_MEMBLOCK
        select HAVE_PERF_EVENTS
+       select HAVE_PERF_REGS
+       select HAVE_PERF_USER_STACK_DUMP
        select IRQ_DOMAIN
        select MODULES_USE_ELF_RELA
        select NO_BOOTMEM

diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
index 41a71ee4c3df42743eb5aa494f72e6287cff55bb..ba962130af1a8d04c0af484483ff148f85348fc8 100644 (file)
--- a/arch/arm64/include/asm/ptrace.h
+++ b/arch/arm64/include/asm/ptrace.h
@@ -67,6 +67,7 @@
 
 /* Architecturally defined mapping between AArch32 and AArch64 registers */
 #define compat_usr(x)  regs[(x)]
+#define compat_fp      regs[11]
 #define compat_sp      regs[13]
 #define compat_lr      regs[14]
 #define compat_sp_hyp  regs[15]

diff --git a/arch/arm64/include/uapi/asm/Kbuild b/arch/arm64/include/uapi/asm/Kbuild
index e4b78bdca19e81b373251cf228917d3a8eab0a60..942376d37d220fc359c6afc35ef3004c9a2074a2 100644 (file)
--- a/arch/arm64/include/uapi/asm/Kbuild
+++ b/arch/arm64/include/uapi/asm/Kbuild
@@ -9,6 +9,7 @@ header-y += byteorder.h
 header-y += fcntl.h
 header-y += hwcap.h
 header-y += kvm_para.h
+header-y += perf_regs.h
 header-y += param.h
 header-y += ptrace.h
 header-y += setup.h

diff --git a/arch/arm64/include/uapi/asm/perf_regs.h b/arch/arm64/include/uapi/asm/perf_regs.h
new file mode 100644 (file)
index 0000000..172b831
--- /dev/null
+++ b/arch/arm64/include/uapi/asm/perf_regs.h
@@ -0,0 +1,40 @@
+#ifndef _ASM_ARM64_PERF_REGS_H
+#define _ASM_ARM64_PERF_REGS_H
+
+enum perf_event_arm_regs {
+       PERF_REG_ARM64_X0,
+       PERF_REG_ARM64_X1,
+       PERF_REG_ARM64_X2,
+       PERF_REG_ARM64_X3,
+       PERF_REG_ARM64_X4,
+       PERF_REG_ARM64_X5,
+       PERF_REG_ARM64_X6,
+       PERF_REG_ARM64_X7,
+       PERF_REG_ARM64_X8,
+       PERF_REG_ARM64_X9,
+       PERF_REG_ARM64_X10,
+       PERF_REG_ARM64_X11,
+       PERF_REG_ARM64_X12,
+       PERF_REG_ARM64_X13,
+       PERF_REG_ARM64_X14,
+       PERF_REG_ARM64_X15,
+       PERF_REG_ARM64_X16,
+       PERF_REG_ARM64_X17,
+       PERF_REG_ARM64_X18,
+       PERF_REG_ARM64_X19,
+       PERF_REG_ARM64_X20,
+       PERF_REG_ARM64_X21,
+       PERF_REG_ARM64_X22,
+       PERF_REG_ARM64_X23,
+       PERF_REG_ARM64_X24,
+       PERF_REG_ARM64_X25,
+       PERF_REG_ARM64_X26,
+       PERF_REG_ARM64_X27,
+       PERF_REG_ARM64_X28,
+       PERF_REG_ARM64_X29,
+       PERF_REG_ARM64_LR,
+       PERF_REG_ARM64_SP,
+       PERF_REG_ARM64_PC,
+       PERF_REG_ARM64_MAX,
+};
+#endif /* _ASM_ARM64_PERF_REGS_H */

diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 7b4b564961d48c4be4fa0df2e1e7ad49c7a57224..db74e559d2ee5b4c54071fcb255169d8ec7eb455 100644 (file)
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -15,8 +15,9 @@ arm64-obj-$(CONFIG_COMPAT)            += sys32.o kuser32.o signal32.o         \
                                           sys_compat.o
 arm64-obj-$(CONFIG_MODULES)            += arm64ksyms.o module.o
 arm64-obj-$(CONFIG_SMP)                        += smp.o smp_spin_table.o smp_psci.o
+arm64-obj-$(CONFIG_PERF_EVENTS)                += perf_regs.o
 arm64-obj-$(CONFIG_HW_PERF_EVENTS)     += perf_event.o
-arm64-obj-$(CONFIG_HAVE_HW_BREAKPOINT)+= hw_breakpoint.o
+arm64-obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
 arm64-obj-$(CONFIG_EARLY_PRINTK)       += early_printk.o
 
 obj-y                                  += $(arm64-obj-y) vdso/

diff --git a/arch/arm64/kernel/perf_regs.c b/arch/arm64/kernel/perf_regs.c
new file mode 100644 (file)
index 0000000..f2d6f0a
--- /dev/null
+++ b/arch/arm64/kernel/perf_regs.c
@@ -0,0 +1,44 @@
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/perf_event.h>
+#include <linux/bug.h>
+#include <asm/perf_regs.h>
+#include <asm/ptrace.h>
+
+u64 perf_reg_value(struct pt_regs *regs, int idx)
+{
+       if (WARN_ON_ONCE((u32)idx >= PERF_REG_ARM64_MAX))
+               return 0;
+
+       /*
+        * Compat (i.e. 32 bit) mode:
+        * - PC has been set in the pt_regs struct in kernel_entry,
+        * - Handle SP and LR here.
+        */
+       if (compat_user_mode(regs)) {
+               if ((u32)idx == PERF_REG_ARM64_SP)
+                       return regs->compat_sp;
+               if ((u32)idx == PERF_REG_ARM64_LR)
+                       return regs->compat_lr;
+       }
+
+       return regs->regs[idx];
+}
+
+#define REG_RESERVED (~((1ULL << PERF_REG_ARM64_MAX) - 1))
+
+int perf_reg_validate(u64 mask)
+{
+       if (!mask || mask & REG_RESERVED)
+               return -EINVAL;
+
+       return 0;
+}
+
+u64 perf_reg_abi(struct task_struct *task)
+{
+       if (is_compat_thread(task_thread_info(task)))
+               return PERF_SAMPLE_REGS_ABI_32;
+       else
+               return PERF_SAMPLE_REGS_ABI_64;
+}