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Date: Tue, 23 Oct 2012 13:30:54 -0400
From: Chris Metcalf <cmetcalf@...era.com>
To: Al Viro <viro@...IV.linux.org.uk>
CC: <linux-kernel@...r.kernel.org>, <linux-arch@...r.kernel.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Catalin Marinas <catalin.marinas@....com>
Subject: [PATCH] arch/tile: eliminate pt_regs trampolines for syscalls
Using the new current_pt_regs() model, we can remove some trampolines
from assembly code and call directly to the C syscall implementations.
rt_sigreturn() and clone() still need some assembly wrapping, but no
longer are passed a pt_regs pointer. sigaltstack() and the
tilepro-specific cmpxchg_badaddr() syscalls are now just straight C.
Signed-off-by: Chris Metcalf <cmetcalf@...era.com>
---
This is based on Al Viro's signal.git#arch-tile branch, which includes
some ARM64 changes and some Tile changes for generic kernel execve.
arch/tile/include/asm/compat.h | 9 +++------
arch/tile/include/asm/syscalls.h | 19 +++++++++++++------
arch/tile/kernel/compat.c | 4 ++--
arch/tile/kernel/compat_signal.c | 10 +++++-----
arch/tile/kernel/intvec_32.S | 13 +------------
arch/tile/kernel/intvec_64.S | 13 +------------
arch/tile/kernel/process.c | 6 +++---
arch/tile/kernel/signal.c | 9 +++++----
arch/tile/kernel/sys.c | 8 +++-----
arch/tile/mm/fault.c | 5 +++--
10 files changed, 39 insertions(+), 57 deletions(-)
diff --git a/arch/tile/include/asm/compat.h b/arch/tile/include/asm/compat.h
index 3bcf1b9..ca61fb4 100644
--- a/arch/tile/include/asm/compat.h
+++ b/arch/tile/include/asm/compat.h
@@ -280,10 +280,9 @@ long compat_sys_rt_sigaction(int sig, struct compat_sigaction __user *act,
size_t sigsetsize);
long compat_sys_rt_sigqueueinfo(int pid, int sig,
struct compat_siginfo __user *uinfo);
-long compat_sys_rt_sigreturn(struct pt_regs *);
+long compat_sys_rt_sigreturn(void);
long compat_sys_sigaltstack(const struct compat_sigaltstack __user *uss_ptr,
- struct compat_sigaltstack __user *uoss_ptr,
- struct pt_regs *);
+ struct compat_sigaltstack __user *uoss_ptr);
long compat_sys_truncate64(char __user *filename, u32 dummy, u32 low, u32 high);
long compat_sys_ftruncate64(unsigned int fd, u32 dummy, u32 low, u32 high);
long compat_sys_pread64(unsigned int fd, char __user *ubuf, size_t count,
@@ -300,9 +299,7 @@ long compat_sys_fallocate(int fd, int mode,
long compat_sys_sched_rr_get_interval(compat_pid_t pid,
struct compat_timespec __user *interval);
-/* These are the intvec_64.S trampolines. */
-long _compat_sys_sigaltstack(const struct compat_sigaltstack __user *uss_ptr,
- struct compat_sigaltstack __user *uoss_ptr);
+/* Assembly trampoline to avoid clobbering r0. */
long _compat_sys_rt_sigreturn(void);
#endif /* _ASM_TILE_COMPAT_H */
diff --git a/arch/tile/include/asm/syscalls.h b/arch/tile/include/asm/syscalls.h
index 0d52992..369696d 100644
--- a/arch/tile/include/asm/syscalls.h
+++ b/arch/tile/include/asm/syscalls.h
@@ -51,8 +51,7 @@ long sys_cacheflush(unsigned long addr, unsigned long len,
#ifndef __tilegx__
/* mm/fault.c */
-long sys_cmpxchg_badaddr(unsigned long address, struct pt_regs *);
-long _sys_cmpxchg_badaddr(unsigned long address);
+long sys_cmpxchg_badaddr(unsigned long address);
#endif
#ifdef CONFIG_COMPAT
@@ -63,15 +62,23 @@ long sys_truncate64(const char __user *path, loff_t length);
long sys_ftruncate64(unsigned int fd, loff_t length);
#endif
-/* These are the intvec*.S trampolines. */
-long _sys_sigaltstack(const stack_t __user *, stack_t __user *);
-long _sys_rt_sigreturn(void);
-long _sys_clone(unsigned long clone_flags, unsigned long newsp,
+/* Provide versions of standard syscalls that use current_pt_regs(). */
+long sys_clone(unsigned long clone_flags, unsigned long newsp,
void __user *parent_tid, void __user *child_tid);
long sys_execve(const char __user *filename,
const char __user *const __user *argv,
const char __user *const __user *envp);
+long sys_rt_sigreturn(void);
+long sys_sigaltstack(const stack_t __user *, stack_t __user *);
+#define sys_clone sys_clone
#define sys_execve sys_execve
+#define sys_rt_sigreturn sys_rt_sigreturn
+#define sys_sigaltstack sys_sigaltstack
+
+/* These are the intvec*.S trampolines. */
+long _sys_rt_sigreturn(void);
+long _sys_clone(unsigned long clone_flags, unsigned long newsp,
+ void __user *parent_tid, void __user *child_tid);
#include <asm-generic/syscalls.h>
diff --git a/arch/tile/kernel/compat.c b/arch/tile/kernel/compat.c
index a8e5a84..a2e8055 100644
--- a/arch/tile/kernel/compat.c
+++ b/arch/tile/kernel/compat.c
@@ -102,9 +102,9 @@ long compat_sys_sched_rr_get_interval(compat_pid_t pid,
#define compat_sys_fadvise64_64 sys32_fadvise64_64
#define compat_sys_readahead sys32_readahead
-/* Call the trampolines to manage pt_regs where necessary. */
-#define compat_sys_sigaltstack _compat_sys_sigaltstack
+/* Call the assembly trampolines where necessary. */
#define compat_sys_rt_sigreturn _compat_sys_rt_sigreturn
+#undef sys_clone
#define sys_clone _sys_clone
/*
diff --git a/arch/tile/kernel/compat_signal.c b/arch/tile/kernel/compat_signal.c
index 08b4fe1..210a9bb 100644
--- a/arch/tile/kernel/compat_signal.c
+++ b/arch/tile/kernel/compat_signal.c
@@ -197,8 +197,7 @@ int copy_siginfo_from_user32(siginfo_t *to, struct compat_siginfo __user *from)
}
long compat_sys_sigaltstack(const struct compat_sigaltstack __user *uss_ptr,
- struct compat_sigaltstack __user *uoss_ptr,
- struct pt_regs *regs)
+ struct compat_sigaltstack __user *uoss_ptr)
{
stack_t uss, uoss;
int ret;
@@ -219,7 +218,7 @@ long compat_sys_sigaltstack(const struct compat_sigaltstack __user *uss_ptr,
set_fs(KERNEL_DS);
ret = do_sigaltstack(uss_ptr ? (stack_t __user __force *)&uss : NULL,
(stack_t __user __force *)&uoss,
- (unsigned long)compat_ptr(regs->sp));
+ (unsigned long)compat_ptr(current_pt_regs()->sp));
set_fs(seg);
if (ret >= 0 && uoss_ptr) {
if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(*uoss_ptr)) ||
@@ -232,8 +231,9 @@ long compat_sys_sigaltstack(const struct compat_sigaltstack __user *uss_ptr,
}
/* The assembly shim for this function arranges to ignore the return value. */
-long compat_sys_rt_sigreturn(struct pt_regs *regs)
+long compat_sys_rt_sigreturn(void)
{
+ struct pt_regs *regs = current_pt_regs();
struct compat_rt_sigframe __user *frame =
(struct compat_rt_sigframe __user *) compat_ptr(regs->sp);
sigset_t set;
@@ -248,7 +248,7 @@ long compat_sys_rt_sigreturn(struct pt_regs *regs)
if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
goto badframe;
- if (compat_sys_sigaltstack(&frame->uc.uc_stack, NULL, regs) != 0)
+ if (compat_sys_sigaltstack(&frame->uc.uc_stack, NULL) != 0)
goto badframe;
return 0;
diff --git a/arch/tile/kernel/intvec_32.S b/arch/tile/kernel/intvec_32.S
index 174b837..f212bf7 100644
--- a/arch/tile/kernel/intvec_32.S
+++ b/arch/tile/kernel/intvec_32.S
@@ -1452,15 +1452,6 @@ STD_ENTRY_LOCAL(bad_intr)
panic "Unhandled interrupt %#x: PC %#lx"
STD_ENDPROC(bad_intr)
-/* Put address of pt_regs in reg and jump. */
-#define PTREGS_SYSCALL(x, reg) \
- STD_ENTRY(_##x); \
- { \
- PTREGS_PTR(reg, PTREGS_OFFSET_BASE); \
- j x \
- }; \
- STD_ENDPROC(_##x)
-
/*
* Special-case sigreturn to not write r0 to the stack on return.
* This is technically more efficient, but it also avoids difficulties
@@ -1476,11 +1467,9 @@ STD_ENTRY_LOCAL(bad_intr)
}; \
STD_ENDPROC(_##x)
-PTREGS_SYSCALL(sys_sigaltstack, r2)
PTREGS_SYSCALL_SIGRETURN(sys_rt_sigreturn, r0)
-PTREGS_SYSCALL(sys_cmpxchg_badaddr, r1)
-/* Save additional callee-saves to pt_regs, put address in r4 and jump. */
+/* Save additional callee-saves to pt_regs and jump to standard function. */
STD_ENTRY(_sys_clone)
push_extra_callee_saves r4
j sys_clone
diff --git a/arch/tile/kernel/intvec_64.S b/arch/tile/kernel/intvec_64.S
index 283efed..54bc9a6 100644
--- a/arch/tile/kernel/intvec_64.S
+++ b/arch/tile/kernel/intvec_64.S
@@ -1181,15 +1181,6 @@ STD_ENTRY_LOCAL(bad_intr)
panic "Unhandled interrupt %#x: PC %#lx"
STD_ENDPROC(bad_intr)
-/* Put address of pt_regs in reg and jump. */
-#define PTREGS_SYSCALL(x, reg) \
- STD_ENTRY(_##x); \
- { \
- PTREGS_PTR(reg, PTREGS_OFFSET_BASE); \
- j x \
- }; \
- STD_ENDPROC(_##x)
-
/*
* Special-case sigreturn to not write r0 to the stack on return.
* This is technically more efficient, but it also avoids difficulties
@@ -1205,14 +1196,12 @@ STD_ENTRY_LOCAL(bad_intr)
}; \
STD_ENDPROC(_##x)
-PTREGS_SYSCALL(sys_sigaltstack, r2)
PTREGS_SYSCALL_SIGRETURN(sys_rt_sigreturn, r0)
#ifdef CONFIG_COMPAT
-PTREGS_SYSCALL(compat_sys_sigaltstack, r2)
PTREGS_SYSCALL_SIGRETURN(compat_sys_rt_sigreturn, r0)
#endif
-/* Save additional callee-saves to pt_regs, put address in r4 and jump. */
+/* Save additional callee-saves to pt_regs and jump to standard function. */
STD_ENTRY(_sys_clone)
push_extra_callee_saves r4
j sys_clone
diff --git a/arch/tile/kernel/process.c b/arch/tile/kernel/process.c
index 58f8fd1..6e7fb4e 100644
--- a/arch/tile/kernel/process.c
+++ b/arch/tile/kernel/process.c
@@ -584,10 +584,10 @@ int do_work_pending(struct pt_regs *regs, u32 thread_info_flags)
}
/* Note there is an implicit fifth argument if (clone_flags & CLONE_SETTLS). */
-SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp,
- void __user *, parent_tidptr, void __user *, child_tidptr,
- struct pt_regs *, regs)
+SYSCALL_DEFINE4(clone, unsigned long, clone_flags, unsigned long, newsp,
+ void __user *, parent_tidptr, void __user *, child_tidptr)
{
+ struct pt_regs *regs = current_pt_regs();
if (!newsp)
newsp = regs->sp;
return do_fork(clone_flags, newsp, regs, 0,
diff --git a/arch/tile/kernel/signal.c b/arch/tile/kernel/signal.c
index 67efb65..657a7ac 100644
--- a/arch/tile/kernel/signal.c
+++ b/arch/tile/kernel/signal.c
@@ -37,10 +37,10 @@
#define DEBUG_SIG 0
-SYSCALL_DEFINE3(sigaltstack, const stack_t __user *, uss,
- stack_t __user *, uoss, struct pt_regs *, regs)
+SYSCALL_DEFINE2(sigaltstack, const stack_t __user *, uss,
+ stack_t __user *, uoss)
{
- return do_sigaltstack(uss, uoss, regs->sp);
+ return do_sigaltstack(uss, uoss, current_pt_regs()->sp);
}
@@ -83,8 +83,9 @@ void signal_fault(const char *type, struct pt_regs *regs,
}
/* The assembly shim for this function arranges to ignore the return value. */
-SYSCALL_DEFINE1(rt_sigreturn, struct pt_regs *, regs)
+SYSCALL_DEFINE0(rt_sigreturn)
{
+ struct pt_regs *regs = current_pt_regs();
struct rt_sigframe __user *frame =
(struct rt_sigframe __user *)(regs->sp);
sigset_t set;
diff --git a/arch/tile/kernel/sys.c b/arch/tile/kernel/sys.c
index 359e76f..02ff5c0 100644
--- a/arch/tile/kernel/sys.c
+++ b/arch/tile/kernel/sys.c
@@ -106,13 +106,11 @@ SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
#define sys_readahead sys32_readahead
#endif
-/* Call the trampolines to manage pt_regs where necessary. */
-#define sys_sigaltstack _sys_sigaltstack
+/* Call the assembly trampolines where necessary. */
+#undef sys_rt_sigreturn
#define sys_rt_sigreturn _sys_rt_sigreturn
+#undef sys_clone
#define sys_clone _sys_clone
-#ifndef __tilegx__
-#define sys_cmpxchg_badaddr _sys_cmpxchg_badaddr
-#endif
/*
* Note that we can't include <linux/unistd.h> here since the header
diff --git a/arch/tile/mm/fault.c b/arch/tile/mm/fault.c
index fe811fa..3d2b81c 100644
--- a/arch/tile/mm/fault.c
+++ b/arch/tile/mm/fault.c
@@ -70,9 +70,10 @@ static noinline void force_sig_info_fault(const char *type, int si_signo,
* Synthesize the fault a PL0 process would get by doing a word-load of
* an unaligned address or a high kernel address.
*/
-SYSCALL_DEFINE2(cmpxchg_badaddr, unsigned long, address,
- struct pt_regs *, regs)
+SYSCALL_DEFINE1(cmpxchg_badaddr, unsigned long, address)
{
+ struct pt_regs *regs = current_pt_regs();
+
if (address >= PAGE_OFFSET)
force_sig_info_fault("atomic segfault", SIGSEGV, SEGV_MAPERR,
address, INT_DTLB_MISS, current, regs);
--
1.7.10.3
--
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