From: Rohan McLure rmclure@linux.ibm.com
[ Upstream commit 016ff72bd2090903715c0f9422a44afbb966f4ee ]
As reported[1] by Arnd, the arch-specific fadvise64_64 and fallocate compatibility handlers assume parameters are passed with 32-bit big-endian ABI. This affects the assignment of odd-even parameter pairs to the high or low words of a 64-bit syscall parameter.
Fix fadvise64_64 fallocate compat handlers to correctly swap upper/lower 32 bits conditioned on endianness.
A future patch will replace the arch-specific compat fallocate with an asm-generic implementation. This patch is intended for ease of back-port.
[1]: https://lore.kernel.org/all/be29926f-226e-48dc-871a-e29a54e80583@www.fastmai...
Fixes: 57f48b4b74e7 ("powerpc/compat_sys: swap hi/lo parts of 64-bit syscall args in LE mode") Reported-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Rohan McLure rmclure@linux.ibm.com Reviewed-by: Arnd Bergmann arnd@arndb.de Reviewed-by: Nicholas Piggin npiggin@gmail.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/20220921065605.1051927-9-rmclure@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/include/asm/syscalls.h | 12 ++++++++++++ arch/powerpc/kernel/sys_ppc32.c | 14 +------------- arch/powerpc/kernel/syscalls.c | 4 ++-- 3 files changed, 15 insertions(+), 15 deletions(-)
diff --git a/arch/powerpc/include/asm/syscalls.h b/arch/powerpc/include/asm/syscalls.h index a2b13e55254f..da40219b303a 100644 --- a/arch/powerpc/include/asm/syscalls.h +++ b/arch/powerpc/include/asm/syscalls.h @@ -8,6 +8,18 @@ #include <linux/types.h> #include <linux/compat.h>
+/* + * long long munging: + * The 32 bit ABI passes long longs in an odd even register pair. + * High and low parts are swapped depending on endian mode, + * so define a macro (similar to mips linux32) to handle that. + */ +#ifdef __LITTLE_ENDIAN__ +#define merge_64(low, high) (((u64)high << 32) | low) +#else +#define merge_64(high, low) (((u64)high << 32) | low) +#endif + struct rtas_args;
asmlinkage long sys_mmap(unsigned long addr, size_t len, diff --git a/arch/powerpc/kernel/sys_ppc32.c b/arch/powerpc/kernel/sys_ppc32.c index 16ff0399a257..719bfc6d1e3f 100644 --- a/arch/powerpc/kernel/sys_ppc32.c +++ b/arch/powerpc/kernel/sys_ppc32.c @@ -56,18 +56,6 @@ unsigned long compat_sys_mmap2(unsigned long addr, size_t len, return sys_mmap(addr, len, prot, flags, fd, pgoff << 12); }
-/* - * long long munging: - * The 32 bit ABI passes long longs in an odd even register pair. - * High and low parts are swapped depending on endian mode, - * so define a macro (similar to mips linux32) to handle that. - */ -#ifdef __LITTLE_ENDIAN__ -#define merge_64(low, high) ((u64)high << 32) | low -#else -#define merge_64(high, low) ((u64)high << 32) | low -#endif - compat_ssize_t compat_sys_pread64(unsigned int fd, char __user *ubuf, compat_size_t count, u32 reg6, u32 pos1, u32 pos2) { @@ -94,7 +82,7 @@ asmlinkage int compat_sys_truncate64(const char __user * path, u32 reg4, asmlinkage long compat_sys_fallocate(int fd, int mode, u32 offset1, u32 offset2, u32 len1, u32 len2) { - return ksys_fallocate(fd, mode, ((loff_t)offset1 << 32) | offset2, + return ksys_fallocate(fd, mode, merge_64(offset1, offset2), merge_64(len1, len2)); }
diff --git a/arch/powerpc/kernel/syscalls.c b/arch/powerpc/kernel/syscalls.c index fc999140bc27..abc3fbb3c490 100644 --- a/arch/powerpc/kernel/syscalls.c +++ b/arch/powerpc/kernel/syscalls.c @@ -98,8 +98,8 @@ long ppc64_personality(unsigned long personality) long ppc_fadvise64_64(int fd, int advice, u32 offset_high, u32 offset_low, u32 len_high, u32 len_low) { - return ksys_fadvise64_64(fd, (u64)offset_high << 32 | offset_low, - (u64)len_high << 32 | len_low, advice); + return ksys_fadvise64_64(fd, merge_64(offset_high, offset_low), + merge_64(len_high, len_low), advice); }
SYSCALL_DEFINE0(switch_endian)