Re: [RFC 4/8] ARM64: Add instruction_pointer_set function

From: Pratyush Anand
Date: Fri Jan 09 2015 - 00:19:48 EST




On Thursday 08 January 2015 10:29 PM, Will Deacon wrote:
On Wed, Dec 31, 2014 at 03:21:20PM +0000, Pratyush Anand wrote:
instruction_pointer_set is needed for uprobe implementation. Hence
define it for ARM64.

Signed-off-by: Pratyush Anand <panand@xxxxxxxxxx>
---
arch/arm64/include/asm/ptrace.h | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
index 24cc048ac3e7..29d9bf5e3635 100644
--- a/arch/arm64/include/asm/ptrace.h
+++ b/arch/arm64/include/asm/ptrace.h
@@ -206,6 +206,12 @@ static inline int valid_user_regs(struct user_pt_regs *regs)
#define instruction_pointer(regs) ((regs)->pc)
#define stack_pointer(regs) ((regs)->sp)

+static inline void instruction_pointer_set(struct pt_regs *regs,
+ unsigned long val)
+{
+ instruction_pointer(regs) = val;
+}

Do you think we could make use of the asm-generic ptrace header to get
this for free? afaict, we just need to implement GET_USP and possibly
GET_FP for the compat case (although it may well be that we still handle
the compat case entirely separately).


Yes, We can use asm-generic for it.

I think , we can also add link_pointer and link_pointer_set in asm-generic/ptrace.h to help with all retprobes.

~Pratyush
Will
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