[PATCH v1 03/15] powerpc/uaccess: Remove __get/put_user_inatomic()

Christophe Leroy
2021-02-25T17:55:04Z

Since commit 662bbcb2747c ("mm, sched: Allow uaccess in atomic with
pagefault_disable()"), __get/put_user() can be used in atomic parts
of the code, therefore the __get/put_user_inatomic() introduced
by commit e68c825bb016 ("[POWERPC] Add inatomic versions of __get_user
and __put_user") have become useless.

powerpc is the only one having such functions. There is a real
intention not to have to provide such _inatomic() helpers, see the
comment in might_fault() in mm/memory.c introduced by
commit 3ee1afa308f2 ("x86: some lock annotations for user
copy paths, v2"):

/*
* it would be nicer only to annotate paths which are not under
* pagefault_disable, however that requires a larger audit and
* providing helpers like get_user_atomic.
*/

So remove __get_user_inatomic() and __put_user_inatomic().

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/include/asm/uaccess.h | 37 -------------------
arch/powerpc/kernel/align.c | 32 ++++++++--------
.../kernel/hw_breakpoint_constraints.c | 2 +-
arch/powerpc/kernel/traps.c | 2 +-
4 files changed, 18 insertions(+), 55 deletions(-)

diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index a08c482b1315..01aea0df4dd0 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -53,11 +53,6 @@ static inline bool __access_ok(unsigned long addr, unsigned long size)
#define __put_user(x, ptr) \
__put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))

-#define __get_user_inatomic(x, ptr) \
- __get_user_nosleep((x), (ptr), sizeof(*(ptr)))
-#define __put_user_inatomic(x, ptr) \
- __put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
-
#ifdef CONFIG_PPC64

#define ___get_user_instr(gu_op, dest, ptr) \
@@ -92,9 +87,6 @@ static inline bool __access_ok(unsigned long addr, unsigned long size)
#define __get_user_instr(x, ptr) \
___get_user_instr(__get_user, x, ptr)

-#define __get_user_instr_inatomic(x, ptr) \
- ___get_user_instr(__get_user_inatomic, x, ptr)
-
extern long __put_user_bad(void);

#define __put_user_size(x, ptr, size, retval) \
@@ -141,20 +133,6 @@ __pu_failed: \
__pu_err; \
})

-#define __put_user_nosleep(x, ptr, size) \
-({ \
- long __pu_err; \
- __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
- __typeof__(*(ptr)) __pu_val = (x); \
- __typeof__(size) __pu_size = (size); \
- \
- __chk_user_ptr(__pu_addr); \
- __put_user_size(__pu_val, __pu_addr, __pu_size, __pu_err); \
- \
- __pu_err; \
-})
-
-
/*
* We don't tell gcc that we are accessing memory, but this is OK
* because we do not write to any memory gcc knows about, so there
@@ -320,21 +298,6 @@ do { \
__gu_err; \
})

-#define __get_user_nosleep(x, ptr, size) \
-({ \
- long __gu_err; \
- __long_type(*(ptr)) __gu_val; \
- __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
- __typeof__(size) __gu_size = (size); \
- \
- __chk_user_ptr(__gu_addr); \
- __get_user_size(__gu_val, __gu_addr, __gu_size, __gu_err); \
- (x) = (__force __typeof__(*(ptr)))__gu_val; \
- \
- __gu_err; \
-})
-
-
/* more complex routines */

extern unsigned long __copy_tofrom_user(void __user *to,
diff --git a/arch/powerpc/kernel/align.c b/arch/powerpc/kernel/align.c
index c7797eb958c7..83b199026a1e 100644
--- a/arch/powerpc/kernel/align.c
+++ b/arch/powerpc/kernel/align.c
@@ -174,18 +174,18 @@ static int emulate_spe(struct pt_regs *regs, unsigned int reg,

switch (nb) {
case 8:
- ret |= __get_user_inatomic(temp.v[0], p++);
- ret |= __get_user_inatomic(temp.v[1], p++);
- ret |= __get_user_inatomic(temp.v[2], p++);
- ret |= __get_user_inatomic(temp.v[3], p++);
+ ret |= __get_user(temp.v[0], p++);
+ ret |= __get_user(temp.v[1], p++);
+ ret |= __get_user(temp.v[2], p++);
+ ret |= __get_user(temp.v[3], p++);
fallthrough;
case 4:
- ret |= __get_user_inatomic(temp.v[4], p++);
- ret |= __get_user_inatomic(temp.v[5], p++);
+ ret |= __get_user(temp.v[4], p++);
+ ret |= __get_user(temp.v[5], p++);
fallthrough;
case 2:
- ret |= __get_user_inatomic(temp.v[6], p++);
- ret |= __get_user_inatomic(temp.v[7], p++);
+ ret |= __get_user(temp.v[6], p++);
+ ret |= __get_user(temp.v[7], p++);
if (unlikely(ret))
return -EFAULT;
}
@@ -259,18 +259,18 @@ static int emulate_spe(struct pt_regs *regs, unsigned int reg,
p = addr;
switch (nb) {
case 8:
- ret |= __put_user_inatomic(data.v[0], p++);
- ret |= __put_user_inatomic(data.v[1], p++);
- ret |= __put_user_inatomic(data.v[2], p++);
- ret |= __put_user_inatomic(data.v[3], p++);
+ ret |= __put_user(data.v[0], p++);
+ ret |= __put_user(data.v[1], p++);
+ ret |= __put_user(data.v[2], p++);
+ ret |= __put_user(data.v[3], p++);
fallthrough;
case 4:
- ret |= __put_user_inatomic(data.v[4], p++);
- ret |= __put_user_inatomic(data.v[5], p++);
+ ret |= __put_user(data.v[4], p++);
+ ret |= __put_user(data.v[5], p++);
fallthrough;
case 2:
- ret |= __put_user_inatomic(data.v[6], p++);
- ret |= __put_user_inatomic(data.v[7], p++);
+ ret |= __put_user(data.v[6], p++);
+ ret |= __put_user(data.v[7], p++);
}
if (unlikely(ret))
return -EFAULT;
diff --git a/arch/powerpc/kernel/hw_breakpoint_constraints.c b/arch/powerpc/kernel/hw_breakpoint_constraints.c
index 867ee4aa026a..675d1f66ab72 100644
--- a/arch/powerpc/kernel/hw_breakpoint_constraints.c
+++ b/arch/powerpc/kernel/hw_breakpoint_constraints.c
@@ -141,7 +141,7 @@ void wp_get_instr_detail(struct pt_regs *regs, struct ppc_inst *instr,
{
struct instruction_op op;

- if (__get_user_instr_inatomic(*instr, (void __user *)regs->nip))
+ if (__get_user_instr(*instr, (void __user *)regs->nip))
return;

analyse_instr(&op, regs, *instr);
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 1583fd1c6010..1fa36bd08efe 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -864,7 +864,7 @@ static void p9_hmi_special_emu(struct pt_regs *regs)
unsigned long ea, msr, msr_mask;
bool swap;

- if (__get_user_inatomic(instr, (unsigned int __user *)regs->nip))
+ if (__get_user(instr, (unsigned int __user *)regs->nip))
return;

/*
--
2.25.0