lkml.org 
[lkml]   [2019]   [Feb]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Date
Subject[PATCH 3.16 239/305] xtensa: fix coprocessor part of ptrace_{get,set}xregs
3.16.63-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Max Filippov <jcmvbkbc@gmail.com>

commit 38a35a78c5e270cbe53c4fef6b0d3c2da90dd849 upstream.

Layout of coprocessor registers in the elf_xtregs_t and
xtregs_coprocessor_t may be different due to alignment. Thus it is not
always possible to copy data between the xtregs_coprocessor_t structure
and the elf_xtregs_t and get correct values for all registers.
Use a table of offsets and sizes of individual coprocessor register
groups to do coprocessor context copying in the ptrace_getxregs and
ptrace_setxregs.
This fixes incorrect coprocessor register values reading from the user
process by the native gdb on an xtensa core with multiple coprocessors
and registers with high alignment requirements.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
arch/xtensa/kernel/ptrace.c | 42 +++++++++++++++++++++++++++++++++----
1 file changed, 38 insertions(+), 4 deletions(-)

--- a/arch/xtensa/kernel/ptrace.c
+++ b/arch/xtensa/kernel/ptrace.c
@@ -124,12 +124,37 @@ int ptrace_setregs(struct task_struct *c
}


+#if XTENSA_HAVE_COPROCESSORS
+#define CP_OFFSETS(cp) \
+ { \
+ .elf_xtregs_offset = offsetof(elf_xtregs_t, cp), \
+ .ti_offset = offsetof(struct thread_info, xtregs_cp.cp), \
+ .sz = sizeof(xtregs_ ## cp ## _t), \
+ }
+
+static const struct {
+ size_t elf_xtregs_offset;
+ size_t ti_offset;
+ size_t sz;
+} cp_offsets[] = {
+ CP_OFFSETS(cp0),
+ CP_OFFSETS(cp1),
+ CP_OFFSETS(cp2),
+ CP_OFFSETS(cp3),
+ CP_OFFSETS(cp4),
+ CP_OFFSETS(cp5),
+ CP_OFFSETS(cp6),
+ CP_OFFSETS(cp7),
+};
+#endif
+
int ptrace_getxregs(struct task_struct *child, void __user *uregs)
{
struct pt_regs *regs = task_pt_regs(child);
struct thread_info *ti = task_thread_info(child);
elf_xtregs_t __user *xtregs = uregs;
int ret = 0;
+ int i __maybe_unused;

if (!access_ok(VERIFY_WRITE, uregs, sizeof(elf_xtregs_t)))
return -EIO;
@@ -137,8 +162,13 @@ int ptrace_getxregs(struct task_struct *
#if XTENSA_HAVE_COPROCESSORS
/* Flush all coprocessor registers to memory. */
coprocessor_flush_all(ti);
- ret |= __copy_to_user(&xtregs->cp0, &ti->xtregs_cp,
- sizeof(xtregs_coprocessor_t));
+
+ for (i = 0; i < ARRAY_SIZE(cp_offsets); ++i)
+ ret |= __copy_to_user((char __user *)xtregs +
+ cp_offsets[i].elf_xtregs_offset,
+ (const char *)ti +
+ cp_offsets[i].ti_offset,
+ cp_offsets[i].sz);
#endif
ret |= __copy_to_user(&xtregs->opt, &regs->xtregs_opt,
sizeof(xtregs->opt));
@@ -154,6 +184,7 @@ int ptrace_setxregs(struct task_struct *
struct pt_regs *regs = task_pt_regs(child);
elf_xtregs_t *xtregs = uregs;
int ret = 0;
+ int i __maybe_unused;

if (!access_ok(VERIFY_READ, uregs, sizeof(elf_xtregs_t)))
return -EFAULT;
@@ -163,8 +194,11 @@ int ptrace_setxregs(struct task_struct *
coprocessor_flush_all(ti);
coprocessor_release_all(ti);

- ret |= __copy_from_user(&ti->xtregs_cp, &xtregs->cp0,
- sizeof(xtregs_coprocessor_t));
+ for (i = 0; i < ARRAY_SIZE(cp_offsets); ++i)
+ ret |= __copy_from_user((char *)ti + cp_offsets[i].ti_offset,
+ (const char __user *)xtregs +
+ cp_offsets[i].elf_xtregs_offset,
+ cp_offsets[i].sz);
#endif
ret |= __copy_from_user(&regs->xtregs_opt, &xtregs->opt,
sizeof(xtregs->opt));
\
 
 \ /
  Last update: 2019-02-03 15:27    [W:0.987 / U:0.028 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site