ARM64: perf: support dwarf unwinding in compat mode

Add support for unwinding using the dwarf information in compat
mode. Using the correct user stack pointer allows perf to record
the frames correctly in the native and compat modes.

Note that although the dwarf frame unwinding works ok using
libunwind in native mode (on ARMv7 & ARMv8), some changes are
required to the libunwind code for the compat mode. Those changes
are posted separately on the libunwind mailing list.

Tested on ARMv8 platform with v8 and compat v7 binaries, the latter
are statically built.

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>

diff --git a/arch/arm64/include/asm/compat.h b/arch/arm64/include/asm/compat.h
index 899af807ef0ff3d789491d6e0ee8d9684886f849..7058eec269abb16ede741ad6be7ab096b27db6d7 100644 (file)
--- a/arch/arm64/include/asm/compat.h
+++ b/arch/arm64/include/asm/compat.h
@@ -214,7 +214,7 @@ static inline compat_uptr_t ptr_to_compat(void __user *uptr)
        return (u32)(unsigned long)uptr;
 }
 
-#define compat_user_stack_pointer() (current_pt_regs()->compat_sp)
+#define compat_user_stack_pointer() (user_stack_pointer(current_pt_regs()))
 
 static inline void __user *arch_compat_alloc_user_space(long len)
 {

diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
index 41a71ee4c3df42743eb5aa494f72e6287cff55bb..c2a199727e4fa1f2d92f541636a7461212b0e4e9 100644 (file)
--- a/arch/arm64/include/asm/ptrace.h
+++ b/arch/arm64/include/asm/ptrace.h
@@ -131,7 +131,7 @@ struct pt_regs {
        (!((regs)->pstate & PSR_F_BIT))
 
 #define user_stack_pointer(regs) \
-       ((regs)->sp)
+       (!compat_user_mode(regs)) ? ((regs)->sp) : ((regs)->compat_sp)
 
 /*
  * Are the current registers suitable for user mode? (used to maintain