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powerpc/ptrace: Convert gpr32_set_common() to user access block

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Use user access block in gpr32_set_common() instead of
repetitive __get_user() which imply repetitive KUAP open/close.

To get it clean, force inlining of the small set of tiny functions
called inside the block.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/bdcb8652c3bb4ab5b8b3bfd08147434be8fc04c9.1615398498.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy
2021-03-10 17:57:07 +00:00
committed by Michael Ellerman
parent 870779f40e
commit 93c043e393
2 changed files with 19 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files
arch/powerpc/include/asm/ptrace.h
+1 -1
View File
@@ -222,7 +222,7 @@ do { \
} while (0)
#endif /* __powerpc64__ */
static inline void set_trap(struct pt_regs *regs, unsigned long val)
static __always_inline void set_trap(struct pt_regs *regs, unsigned long val)
{
regs->trap = (regs->trap & TRAP_FLAGS_MASK) | (val & ~TRAP_FLAGS_MASK);
}
arch/powerpc/kernel/ptrace/ptrace-view.c
+18 -12
View File
@@ -111,7 +111,7 @@ static unsigned long get_user_msr(struct task_struct *task)
return task->thread.regs->msr | task->thread.fpexc_mode;
}
static int set_user_msr(struct task_struct *task, unsigned long msr)
static __always_inline int set_user_msr(struct task_struct *task, unsigned long msr)
{
task->thread.regs->msr &= ~MSR_DEBUGCHANGE;
task->thread.regs->msr |= msr & MSR_DEBUGCHANGE;
@@ -147,7 +147,7 @@ static int set_user_dscr(struct task_struct *task, unsigned long dscr)
* We prevent mucking around with the reserved area of trap
* which are used internally by the kernel.
*/
static int set_user_trap(struct task_struct *task, unsigned long trap)
static __always_inline int set_user_trap(struct task_struct *task, unsigned long trap)
{
set_trap(task->thread.regs, trap);
return 0;
@@ -661,6 +661,9 @@ int gpr32_set_common(struct task_struct *target,
const compat_ulong_t __user *u = ubuf;
compat_ulong_t reg;
if (!kbuf && !user_read_access_begin(u, count))
return -EFAULT;
pos /= sizeof(reg);
count /= sizeof(reg);
@@ -669,8 +672,7 @@ int gpr32_set_common(struct task_struct *target,
regs[pos++] = *k++;
else
for (; count > 0 && pos < PT_MSR; --count) {
if (__get_user(reg, u++))
return -EFAULT;
unsafe_get_user(reg, u++, Efault);
regs[pos++] = reg;
}
@@ -678,8 +680,8 @@ int gpr32_set_common(struct task_struct *target,
if (count > 0 && pos == PT_MSR) {
if (kbuf)
reg = *k++;
else if (__get_user(reg, u++))
return -EFAULT;
else
unsafe_get_user(reg, u++, Efault);
set_user_msr(target, reg);
++pos;
--count;
@@ -692,24 +694,24 @@ int gpr32_set_common(struct task_struct *target,
++k;
} else {
for (; count > 0 && pos <= PT_MAX_PUT_REG; --count) {
if (__get_user(reg, u++))
return -EFAULT;
unsafe_get_user(reg, u++, Efault);
regs[pos++] = reg;
}
for (; count > 0 && pos < PT_TRAP; --count, ++pos)
if (__get_user(reg, u++))
return -EFAULT;
unsafe_get_user(reg, u++, Efault);
}
if (count > 0 && pos == PT_TRAP) {
if (kbuf)
reg = *k++;
else if (__get_user(reg, u++))
return -EFAULT;
else
unsafe_get_user(reg, u++, Efault);
set_user_trap(target, reg);
++pos;
--count;
}
if (!kbuf)
user_read_access_end();
kbuf = k;
ubuf = u;
@@ -717,6 +719,10 @@ int gpr32_set_common(struct task_struct *target,
count *= sizeof(reg);
return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
(PT_TRAP + 1) * sizeof(reg), -1);
Efault:
user_read_access_end();
return -EFAULT;
}
static int gpr32_get(struct task_struct *target,