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arm64: uaccess: Move existing GCS accessors definitions to gcs.h

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We are going to add some additional GCS access helpers to gcs.h in
order to avoid some forward reference problems with uaccess.

In preparation for that, lets move the existing gcssttr() and
put_user_gcs() routines into gcs.h where it makes sense to keep all
the accessors together. Further, the code which uses them already
includes gcs.h and there is an existing CONFIG_ARM64_GCS check we can
reuse. The GCSSTTR instruction description comment is corrected during
the move.

Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Jeremy Linton 2025-08-24 22:34:16 -05:00 committed by Will Deacon
parent 47687aa4d9
commit ea920b50ac
2 changed files with 36 additions and 41 deletions
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37
arch/arm64/include/asm/gcs.h
View File

@ -21,7 +21,7 @@ static inline void gcsstr(u64 *addr, u64 val)
register u64 *_addr __asm__ ("x0") = addr;
register long _val __asm__ ("x1") = val;
/* GCSSTTR x1, x0 */
/* GCSSTTR x1, [x0] */
asm volatile(
".inst 0xd91f1c01\n"
:
@ -81,6 +81,41 @@ static inline int gcs_check_locked(struct task_struct *task,
return 0;
}
static inline int gcssttr(unsigned long __user *addr, unsigned long val)
{
register unsigned long __user *_addr __asm__ ("x0") = addr;
register unsigned long _val __asm__ ("x1") = val;
int err = 0;
/* GCSSTTR x1, [x0] */
asm volatile(
"1: .inst 0xd91f1c01\n"
"2: \n"
_ASM_EXTABLE_UACCESS_ERR(1b, 2b, %w0)
: "+r" (err)
: "rZ" (_val), "r" (_addr)
: "memory");
return err;
}
static inline void put_user_gcs(unsigned long val, unsigned long __user *addr,
int *err)
{
int ret;
if (!access_ok((char __user *)addr, sizeof(u64))) {
*err = -EFAULT;
return;
}
uaccess_ttbr0_enable();
ret = gcssttr(addr, val);
if (ret != 0)
*err = ret;
uaccess_ttbr0_disable();
}
#else
static inline bool task_gcs_el0_enabled(struct task_struct *task)

40
arch/arm64/include/asm/uaccess.h
View File

@ -502,44 +502,4 @@ static inline size_t probe_subpage_writeable(const char __user *uaddr,
#endif /* CONFIG_ARCH_HAS_SUBPAGE_FAULTS */
#ifdef CONFIG_ARM64_GCS
static inline int gcssttr(unsigned long __user *addr, unsigned long val)
{
register unsigned long __user *_addr __asm__ ("x0") = addr;
register unsigned long _val __asm__ ("x1") = val;
int err = 0;
/* GCSSTTR x1, x0 */
asm volatile(
"1: .inst 0xd91f1c01\n"
"2: \n"
_ASM_EXTABLE_UACCESS_ERR(1b, 2b, %w0)
: "+r" (err)
: "rZ" (_val), "r" (_addr)
: "memory");
return err;
}
static inline void put_user_gcs(unsigned long val, unsigned long __user *addr,
int *err)
{
int ret;
if (!access_ok((char __user *)addr, sizeof(u64))) {
*err = -EFAULT;
return;
}
uaccess_ttbr0_enable();
ret = gcssttr(addr, val);
if (ret != 0)
*err = ret;
uaccess_ttbr0_disable();
}
#endif /* CONFIG_ARM64_GCS */
#endif /* __ASM_UACCESS_H */