diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2020-11-19 17:02:21 +0100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-11-26 22:05:42 +1100 |
| commit | 640586f8af356096e084d69a9909d217852bde48 (patch) | |
| tree | f25479b356c791dfd0087c2fd5f7d18638d71d63 | |
| parent | 20fa40b147bda9b976227c11ea7afb369827e7d4 (diff) | |
powerpc/ptrace: Simplify gpr_get()/tm_cgpr_get()
gpr_get() does membuf_write() twice to override pt_regs->msr in
between. We can call membuf_write() once and change ->msr in the
kernel buffer, this simplifies the code and the next fix.
The patch adds a new simple helper, membuf_at(offs), it returns the
new membuf which can be safely used after membuf_write().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
[mpe: Fixup some minor whitespace issues noticed by Christophe]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201119160221.GA5188@redhat.com
| -rw-r--r-- | arch/powerpc/kernel/ptrace/ptrace-tm.c | 12 | ||||
| -rw-r--r-- | arch/powerpc/kernel/ptrace/ptrace-view.c | 10 | ||||
| -rw-r--r-- | include/linux/regset.h | 12 |
3 files changed, 19 insertions, 15 deletions
diff --git a/arch/powerpc/kernel/ptrace/ptrace-tm.c b/arch/powerpc/kernel/ptrace/ptrace-tm.c index 54f2d076206f..f15cbbab45b7 100644 --- a/arch/powerpc/kernel/ptrace/ptrace-tm.c +++ b/arch/powerpc/kernel/ptrace/ptrace-tm.c @@ -86,6 +86,8 @@ int tm_cgpr_active(struct task_struct *target, const struct user_regset *regset) int tm_cgpr_get(struct task_struct *target, const struct user_regset *regset, struct membuf to) { + struct membuf to_msr = membuf_at(&to, offsetof(struct pt_regs, msr)); + if (!cpu_has_feature(CPU_FTR_TM)) return -ENODEV; @@ -96,16 +98,10 @@ int tm_cgpr_get(struct task_struct *target, const struct user_regset *regset, flush_fp_to_thread(target); flush_altivec_to_thread(target); - membuf_write(&to, &target->thread.ckpt_regs, - offsetof(struct pt_regs, msr)); - membuf_store(&to, get_user_ckpt_msr(target)); + membuf_write(&to, &target->thread.ckpt_regs, sizeof(struct user_pt_regs)); - BUILD_BUG_ON(offsetof(struct pt_regs, orig_gpr3) != - offsetof(struct pt_regs, msr) + sizeof(long)); + membuf_store(&to_msr, get_user_ckpt_msr(target)); - membuf_write(&to, &target->thread.ckpt_regs.orig_gpr3, - sizeof(struct user_pt_regs) - - offsetof(struct pt_regs, orig_gpr3)); return membuf_zero(&to, ELF_NGREG * sizeof(unsigned long) - sizeof(struct user_pt_regs)); } diff --git a/arch/powerpc/kernel/ptrace/ptrace-view.c b/arch/powerpc/kernel/ptrace/ptrace-view.c index 7e6478e7ed07..299e0b6d709d 100644 --- a/arch/powerpc/kernel/ptrace/ptrace-view.c +++ b/arch/powerpc/kernel/ptrace/ptrace-view.c @@ -217,6 +217,7 @@ int ptrace_put_reg(struct task_struct *task, int regno, unsigned long data) static int gpr_get(struct task_struct *target, const struct user_regset *regset, struct membuf to) { + struct membuf to_msr = membuf_at(&to, offsetof(struct pt_regs, msr)); int i; if (target->thread.regs == NULL) @@ -228,15 +229,10 @@ static int gpr_get(struct task_struct *target, const struct user_regset *regset, target->thread.regs->gpr[i] = NV_REG_POISON; } - membuf_write(&to, target->thread.regs, offsetof(struct pt_regs, msr)); - membuf_store(&to, get_user_msr(target)); + membuf_write(&to, target->thread.regs, sizeof(struct user_pt_regs)); - BUILD_BUG_ON(offsetof(struct pt_regs, orig_gpr3) != - offsetof(struct pt_regs, msr) + sizeof(long)); + membuf_store(&to_msr, get_user_msr(target)); - membuf_write(&to, &target->thread.regs->orig_gpr3, - sizeof(struct user_pt_regs) - - offsetof(struct pt_regs, orig_gpr3)); return membuf_zero(&to, ELF_NGREG * sizeof(unsigned long) - sizeof(struct user_pt_regs)); } diff --git a/include/linux/regset.h b/include/linux/regset.h index c3403f328257..a00765f0e8cf 100644 --- a/include/linux/regset.h +++ b/include/linux/regset.h @@ -46,6 +46,18 @@ static inline int membuf_write(struct membuf *s, const void *v, size_t size) return s->left; } +static inline struct membuf membuf_at(const struct membuf *s, size_t offs) +{ + struct membuf n = *s; + + if (offs > n.left) + offs = n.left; + n.p += offs; + n.left -= offs; + + return n; +} + /* current s->p must be aligned for v; v must be a scalar */ #define membuf_store(s, v) \ ({ \ |