From 2225a122ae26d542bdce523d9d87a4a7ba10e07b Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Thu, 11 Feb 2010 11:51:00 -0800 Subject: ptrace: Add support for generic PTRACE_GETREGSET/PTRACE_SETREGSET Generic support for PTRACE_GETREGSET/PTRACE_SETREGSET commands which export the regsets supported by each architecture using the correponding NT_* types. These NT_* types are already part of the userland ABI, used in representing the architecture specific register sets as different NOTES in an ELF core file. 'addr' parameter for the ptrace system call encode the REGSET type (using the corresppnding NT_* type) and the 'data' parameter points to the struct iovec having the user buffer and the length of that buffer. struct iovec iov = { buf, len}; ret = ptrace(PTRACE_GETREGSET/PTRACE_SETREGSET, pid, NT_XXX_TYPE, &iov); On successful completion, iov.len will be updated by the kernel specifying how much the kernel has written/read to/from the user's iov.buf. x86 extended state registers are primarily exported using this interface. Signed-off-by: Suresh Siddha LKML-Reference: <20100211195614.886724710@sbs-t61.sc.intel.com> Acked-by: Hongjiu Lu Cc: Roland McGrath Signed-off-by: H. Peter Anvin --- include/linux/ptrace.h | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'include/linux/ptrace.h') diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h index 56f2d63a5cb..dbfa821d5a6 100644 --- a/include/linux/ptrace.h +++ b/include/linux/ptrace.h @@ -27,6 +27,21 @@ #define PTRACE_GETSIGINFO 0x4202 #define PTRACE_SETSIGINFO 0x4203 +/* + * Generic ptrace interface that exports the architecture specific regsets + * using the corresponding NT_* types (which are also used in the core dump). + * + * This interface usage is as follows: + * struct iovec iov = { buf, len}; + * + * ret = ptrace(PTRACE_GETREGSET/PTRACE_SETREGSET, pid, NT_XXX_TYPE, &iov); + * + * On the successful completion, iov.len will be updated by the kernel, + * specifying how much the kernel has written/read to/from the user's iov.buf. + */ +#define PTRACE_GETREGSET 0x4204 +#define PTRACE_SETREGSET 0x4205 + /* options set using PTRACE_SETOPTIONS */ #define PTRACE_O_TRACESYSGOOD 0x00000001 #define PTRACE_O_TRACEFORK 0x00000002 -- cgit v1.2.3 From c6a0dd7ec6fb2d4927979ed4dc562fc5c122d826 Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Mon, 22 Feb 2010 14:51:32 -0800 Subject: ptrace: Fix ptrace_regset() comments and diagnose errors specifically Return -EINVAL for the bad size and for unrecognized NT_* type in ptrace_regset() instead of -EIO. Also update the comments for this ptrace interface with more clarifications. Requested-by: Roland McGrath Requested-by: Oleg Nesterov Signed-off-by: Suresh Siddha LKML-Reference: <20100222225240.397523600@sbs-t61.sc.intel.com> Acked-by: Roland McGrath Signed-off-by: H. Peter Anvin --- include/linux/ptrace.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux/ptrace.h') diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h index dbfa821d5a6..c5eab89da51 100644 --- a/include/linux/ptrace.h +++ b/include/linux/ptrace.h @@ -30,6 +30,11 @@ /* * Generic ptrace interface that exports the architecture specific regsets * using the corresponding NT_* types (which are also used in the core dump). + * Please note that the NT_PRSTATUS note type in a core dump contains a full + * 'struct elf_prstatus'. But the user_regset for NT_PRSTATUS contains just the + * elf_gregset_t that is the pr_reg field of 'struct elf_prstatus'. For all the + * other user_regset flavors, the user_regset layout and the ELF core dump note + * payload are exactly the same layout. * * This interface usage is as follows: * struct iovec iov = { buf, len}; -- cgit v1.2.3 From dacbe41f776db0a5a9aee1e41594f405c95778a5 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 10 Mar 2010 15:22:46 -0800 Subject: ptrace: move user_enable_single_step & co prototypes to linux/ptrace.h While in theory user_enable_single_step/user_disable_single_step/ user_enable_blockstep could also be provided as an inline or macro there's no good reason to do so, and having the prototype in one places keeps code size and confusion down. Roland said: The original thought there was that user_enable_single_step() et al might well be only an instruction or three on a sane machine (as if we have any of those!), and since there is only one call site inlining would be beneficial. But I agree that there is no strong reason to care about inlining it. As to the arch changes, there is only one thought I'd add to the record. It was always my thinking that for an arch where PTRACE_SINGLESTEP does text-modifying breakpoint insertion, user_enable_single_step() should not be provided. That is, arch_has_single_step()=>true means that there is an arch facility with "pure" semantics that does not have any unexpected side effects. Inserting a breakpoint might do very unexpected strange things in multi-threaded situations. Aside from that, it is a peculiar side effect that user_{enable,disable}_single_step() should cause COW de-sharing of text pages and so forth. For PTRACE_SINGLESTEP, all these peculiarities are the status quo ante for that arch, so having arch_ptrace() itself do those is one thing. But for building other things in the future, it is nicer to have a uniform "pure" semantics that arch-independent code can expect. OTOH, all such arch issues are really up to the arch maintainer. As of today, there is nothing but ptrace using user_enable_single_step() et al so it's a distinction without a practical difference. If/when there are other facilities that use user_enable_single_step() and might care, the affected arch's can revisit the question when someone cares about the quality of the arch support for said new facility. Signed-off-by: Christoph Hellwig Cc: Oleg Nesterov Cc: Roland McGrath Acked-by: David Howells Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/ptrace.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux/ptrace.h') diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h index c5eab89da51..e1fb6072997 100644 --- a/include/linux/ptrace.h +++ b/include/linux/ptrace.h @@ -264,6 +264,9 @@ static inline void user_enable_single_step(struct task_struct *task) static inline void user_disable_single_step(struct task_struct *task) { } +#else +extern void user_enable_single_step(struct task_struct *); +extern void user_disable_single_step(struct task_struct *); #endif /* arch_has_single_step */ #ifndef arch_has_block_step @@ -291,6 +294,8 @@ static inline void user_enable_block_step(struct task_struct *task) { BUG(); /* This can never be called. */ } +#else +extern void user_enable_block_step(struct task_struct *); #endif /* arch_has_block_step */ #ifdef ARCH_HAS_USER_SINGLE_STEP_INFO -- cgit v1.2.3