From: Sami Tolvanen samitolvanen@google.com
[ Upstream commit a9ad73295cc1e3af0253eee7d08943b2419444c4 ]
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: 08d0ce30e0e4 ("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 Signed-off-by: Sasha Levin sashal@kernel.org --- arch/riscv/include/asm/syscall_wrapper.h | 53 +++++++++++++++++------- 1 file changed, 39 insertions(+), 14 deletions(-)
diff --git a/arch/riscv/include/asm/syscall_wrapper.h b/arch/riscv/include/asm/syscall_wrapper.h index eeec04b7dae67..980094c2e9761 100644 --- a/arch/riscv/include/asm/syscall_wrapper.h +++ b/arch/riscv/include/asm/syscall_wrapper.h @@ -12,25 +12,51 @@
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__)); \ - asmlinkage long __riscv_compat_sys##name(const struct pt_regs *regs) \ + __SYSCALL_SE_DEFINEx(x, compat_sys, name, __VA_ARGS__) \ { \ - return __se_compat_sys##name(SC_RISCV_REGS_TO_ARGS(x,__VA_ARGS__)); \ + return __do_compat_sys##name(__MAP(x,__SC_DELOUSE,__VA_ARGS__)); \ } \ - static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \ + asmlinkage long __riscv_compat_sys##name(const struct pt_regs *regs) \ { \ - return __do_compat_sys##name(__MAP(x,__SC_DELOUSE,__VA_ARGS__)); \ + return __se_compat_sys##name(SC_RISCV_REGS_TO_ARGS(x,__VA_ARGS__)); \ } \ static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))
@@ -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) \