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riscv: Fix syscall wrapper for >word-size arguments 

The current syscall wrapper macros break 64-bit arguments on
rv32 because they only guarantee the first N input registers are
passed to syscalls that accept N arguments. According to the
calling convention, values twice the word size reside in register
pairs and as a result, syscall arguments don't always have a
direct register mapping on rv32.

Instead of using `__MAP(x,__SC_LONG,__VA_ARGS__)` to declare the
type of the `__se(_compat)_sys_*` functions on rv32, change the
function declarations to accept `ulong` arguments and alias them
to the actual syscall implementations, similarly to the existing
macros in include/linux/syscalls.h. This matches previous
behavior and ensures registers are passed to syscalls as-is, no
matter which argument types they expect.

Fixes: 08d0ce30e0 ("riscv: Implement syscall wrappers")
Reported-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Link: https://lore.kernel.org/r/20240311193143.2981310-2-samitolvanen@google.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Sami Tolvanen 2024-03-11 19:31:44 +00:00 committed by Palmer Dabbelt
parent eeb7a8933e
commit a9ad73295c
No known key found for this signature in database
GPG Key ID: 2E1319F35FBB1889
1 changed files with 39 additions and 14 deletions
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53
arch/riscv/include/asm/syscall_wrapper.h
View File

@ -12,26 +12,52 @@
asmlinkage long __riscv_sys_ni_syscall(const struct pt_regs *);
#define SC_RISCV_REGS_TO_ARGS(x, ...) \
__MAP(x,__SC_ARGS \
,,regs->orig_a0,,regs->a1,,regs->a2 \
#ifdef CONFIG_64BIT
#define __SYSCALL_SE_DEFINEx(x, prefix, name, ...) \
static long __se_##prefix##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
static long __se_##prefix##name(__MAP(x,__SC_LONG,__VA_ARGS__))
#define SC_RISCV_REGS_TO_ARGS(x, ...) \
__MAP(x,__SC_ARGS \
,,regs->orig_a0,,regs->a1,,regs->a2 \
,,regs->a3,,regs->a4,,regs->a5,,regs->a6)
#else
/*
* Use type aliasing to ensure registers a0-a6 are correctly passed to the syscall
* implementation when >word-size arguments are used.
*/
#define __SYSCALL_SE_DEFINEx(x, prefix, name, ...) \
__diag_push(); \
__diag_ignore(GCC, 8, "-Wattribute-alias", \
"Type aliasing is used to sanitize syscall arguments"); \
static long __se_##prefix##name(ulong, ulong, ulong, ulong, ulong, ulong, \
ulong) \
__attribute__((alias(__stringify(___se_##prefix##name)))); \
__diag_pop(); \
static long noinline ___se_##prefix##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
static long ___se_##prefix##name(__MAP(x,__SC_LONG,__VA_ARGS__))
#define SC_RISCV_REGS_TO_ARGS(x, ...) \
regs->orig_a0,regs->a1,regs->a2,regs->a3,regs->a4,regs->a5,regs->a6
#endif /* CONFIG_64BIT */
#ifdef CONFIG_COMPAT
#define COMPAT_SYSCALL_DEFINEx(x, name, ...) \
asmlinkage long __riscv_compat_sys##name(const struct pt_regs *regs); \
ALLOW_ERROR_INJECTION(__riscv_compat_sys##name, ERRNO); \
static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \
__SYSCALL_SE_DEFINEx(x, compat_sys, name, __VA_ARGS__) \
{ \
return __do_compat_sys##name(__MAP(x,__SC_DELOUSE,__VA_ARGS__)); \
} \
asmlinkage long __riscv_compat_sys##name(const struct pt_regs *regs) \
{ \
return __se_compat_sys##name(SC_RISCV_REGS_TO_ARGS(x,__VA_ARGS__)); \
} \
static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \
{ \
return __do_compat_sys##name(__MAP(x,__SC_DELOUSE,__VA_ARGS__)); \
} \
static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))
#define COMPAT_SYSCALL_DEFINE0(sname) \
@ -51,19 +77,18 @@ asmlinkage long __riscv_sys_ni_syscall(const struct pt_regs *);
#define __SYSCALL_DEFINEx(x, name, ...) \
asmlinkage long __riscv_sys##name(const struct pt_regs *regs); \
ALLOW_ERROR_INJECTION(__riscv_sys##name, ERRNO); \
static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \
asmlinkage long __riscv_sys##name(const struct pt_regs *regs) \
{ \
return __se_sys##name(SC_RISCV_REGS_TO_ARGS(x,__VA_ARGS__)); \
} \
static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \
__SYSCALL_SE_DEFINEx(x, sys, name, __VA_ARGS__) \
{ \
long ret = __do_sys##name(__MAP(x,__SC_CAST,__VA_ARGS__)); \
__MAP(x,__SC_TEST,__VA_ARGS__); \
__PROTECT(x, ret,__MAP(x,__SC_ARGS,__VA_ARGS__)); \
return ret; \
} \
asmlinkage long __riscv_sys##name(const struct pt_regs *regs) \
{ \
return __se_sys##name(SC_RISCV_REGS_TO_ARGS(x,__VA_ARGS__)); \
} \
static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))
#define SYSCALL_DEFINE0(sname) \