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authorJames Hogan <james.hogan@imgtec.com>2017-05-31 16:19:48 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-07-27 15:06:07 -0700
commitf87aa1203910981bcd3fc0b6373e5eb59eac4778 (patch)
tree6803c424c404d521df7bfc16edd37b1938e5b5c0 /arch
parenta0ee41298926bf21379b54549199deac2c0b249a (diff)
downloadlinux-linaro-stable-f87aa1203910981bcd3fc0b6373e5eb59eac4778.tar.gz
MIPS: Save static registers before sysmips
commit 49955d84cd9ccdca5a16a495e448e1a06fad9e49 upstream. The MIPS sysmips system call handler may return directly from the MIPS_ATOMIC_SET case (mips_atomic_set()) to syscall_exit. This path restores the static (callee saved) registers, however they won't have been saved on entry to the system call. Use the save_static_function() macro to create a __sys_sysmips wrapper function which saves the static registers before calling sys_sysmips, so that the correct static register state is restored by syscall_exit. Fixes: f1e39a4a616c ("MIPS: Rewrite sysmips(MIPS_ATOMIC_SET, ...) in C with inline assembler") Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/16149/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/mips/kernel/scall32-o32.S2
-rw-r--r--arch/mips/kernel/scall64-64.S2
-rw-r--r--arch/mips/kernel/scall64-n32.S2
-rw-r--r--arch/mips/kernel/scall64-o32.S2
-rw-r--r--arch/mips/kernel/syscall.c6
5 files changed, 10 insertions, 4 deletions
diff --git a/arch/mips/kernel/scall32-o32.S b/arch/mips/kernel/scall32-o32.S
index 2d23c834ba96..29b0c5f978e4 100644
--- a/arch/mips/kernel/scall32-o32.S
+++ b/arch/mips/kernel/scall32-o32.S
@@ -372,7 +372,7 @@ EXPORT(sys_call_table)
PTR sys_writev
PTR sys_cacheflush
PTR sys_cachectl
- PTR sys_sysmips
+ PTR __sys_sysmips
PTR sys_ni_syscall /* 4150 */
PTR sys_getsid
PTR sys_fdatasync
diff --git a/arch/mips/kernel/scall64-64.S b/arch/mips/kernel/scall64-64.S
index deac63315d0e..a6323a969919 100644
--- a/arch/mips/kernel/scall64-64.S
+++ b/arch/mips/kernel/scall64-64.S
@@ -312,7 +312,7 @@ EXPORT(sys_call_table)
PTR sys_sched_getaffinity
PTR sys_cacheflush
PTR sys_cachectl
- PTR sys_sysmips
+ PTR __sys_sysmips
PTR sys_io_setup /* 5200 */
PTR sys_io_destroy
PTR sys_io_getevents
diff --git a/arch/mips/kernel/scall64-n32.S b/arch/mips/kernel/scall64-n32.S
index ee93d5fe61d7..e0fdca8d3abe 100644
--- a/arch/mips/kernel/scall64-n32.S
+++ b/arch/mips/kernel/scall64-n32.S
@@ -298,7 +298,7 @@ EXPORT(sysn32_call_table)
PTR compat_sys_sched_getaffinity
PTR sys_cacheflush
PTR sys_cachectl
- PTR sys_sysmips
+ PTR __sys_sysmips
PTR compat_sys_io_setup /* 6200 */
PTR sys_io_destroy
PTR compat_sys_io_getevents
diff --git a/arch/mips/kernel/scall64-o32.S b/arch/mips/kernel/scall64-o32.S
index b77052ec6fb2..87c697181d25 100644
--- a/arch/mips/kernel/scall64-o32.S
+++ b/arch/mips/kernel/scall64-o32.S
@@ -367,7 +367,7 @@ EXPORT(sys32_call_table)
PTR compat_sys_writev
PTR sys_cacheflush
PTR sys_cachectl
- PTR sys_sysmips
+ PTR __sys_sysmips
PTR sys_ni_syscall /* 4150 */
PTR sys_getsid
PTR sys_fdatasync
diff --git a/arch/mips/kernel/syscall.c b/arch/mips/kernel/syscall.c
index 8c222d390c48..4234b2d726c5 100644
--- a/arch/mips/kernel/syscall.c
+++ b/arch/mips/kernel/syscall.c
@@ -202,6 +202,12 @@ static inline int mips_atomic_set(unsigned long addr, unsigned long new)
unreachable();
}
+/*
+ * mips_atomic_set() normally returns directly via syscall_exit potentially
+ * clobbering static registers, so be sure to preserve them.
+ */
+save_static_function(sys_sysmips);
+
SYSCALL_DEFINE3(sysmips, long, cmd, long, arg1, long, arg2)
{
switch (cmd) {