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Date: Fri, 18 Jan 2013 17:54:51 +0530
From: Vineet Gupta <Vineet.Gupta1@...opsys.com>
To: <linux-arch@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC: <arnd@...db.de>, Vineet Gupta <Vineet.Gupta1@...opsys.com>,
Al Viro <viro@...IV.linux.org.uk>
Subject: [PATCH v2 37/76] ARC: Switch to generic kernel_execve() and sys_execve()
Signed-off-by: Vineet Gupta <vgupta@...opsys.com>
Cc: Al Viro <viro@...IV.linux.org.uk>
---
arch/arc/include/asm/ptrace.h | 8 +++++++
arch/arc/include/asm/syscalls.h | 1 -
arch/arc/include/asm/unistd.h | 3 ++
arch/arc/kernel/entry.S | 18 ++++++++-------
arch/arc/kernel/process.c | 44 ---------------------------------------
arch/arc/kernel/sys.c | 1 -
6 files changed, 21 insertions(+), 54 deletions(-)
diff --git a/arch/arc/include/asm/ptrace.h b/arch/arc/include/asm/ptrace.h
index 92ef198..e4e1ac6 100644
--- a/arch/arc/include/asm/ptrace.h
+++ b/arch/arc/include/asm/ptrace.h
@@ -133,6 +133,14 @@ struct user_regs_struct {
#define syscall_wont_restart(regs) (regs->orig_r8 |= orig_r8_IS_SCALL_RESTARTED)
#define syscall_restartable(regs) !(regs->orig_r8 & orig_r8_IS_SCALL_RESTARTED)
+#define current_pt_regs() \
+({ \
+ /* open-coded current_thread_info() */ \
+ register unsigned long sp asm ("sp"); \
+ unsigned long pg_start = (sp & ~(THREAD_SIZE - 1)); \
+ (struct pt_regs *)(pg_start + THREAD_SIZE - 4) - 1; \
+})
+
#endif /* !__ASSEMBLY__ */
#define orig_r8_IS_SCALL 0x0001
diff --git a/arch/arc/include/asm/syscalls.h b/arch/arc/include/asm/syscalls.h
index cf5d2f5..e53a534 100644
--- a/arch/arc/include/asm/syscalls.h
+++ b/arch/arc/include/asm/syscalls.h
@@ -15,7 +15,6 @@
#include <linux/linkage.h>
#include <linux/types.h>
-int sys_execve_wrapper(int, int, int);
int sys_clone_wrapper(int, int, int, int, int);
int sys_fork_wrapper(void);
int sys_vfork_wrapper(void);
diff --git a/arch/arc/include/asm/unistd.h b/arch/arc/include/asm/unistd.h
index 6a2d101..003b2cf 100644
--- a/arch/arc/include/asm/unistd.h
+++ b/arch/arc/include/asm/unistd.h
@@ -8,6 +8,9 @@
/******** no-legacy-syscalls-ABI *******/
+#define __ARCH_WANT_KERNEL_EXECVE
+#define __ARCH_WANT_SYS_EXECVE
+
#define sys_mmap2 sys_mmap_pgoff
#include <asm-generic/unistd.h>
diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S
index e76b432..d2cad3c 100644
--- a/arch/arc/kernel/entry.S
+++ b/arch/arc/kernel/entry.S
@@ -586,15 +586,17 @@ ARC_ENTRY ret_from_kernel_thread
j @sys_exit
ARC_EXIT ret_from_kernel_thread
-;################### Special Sys Call Wrappers ##########################
-
-ARC_ENTRY sys_execve_wrapper
- ; copy pointer to pt_regs as a parameter
- mov r3, sp
- bl @sys_execve
+; When we land here, pt_regs have already been updated in-place correctly
+; for return to user mode.
+; However the call stack leading to kernel_execve() from say
+; ____call_usermodehelper() would make SP != pt_regs.
+; Thus we need to set SP to pt_regs as passed by kernel_execve() to us.
+ARC_ENTRY ret_from_kernel_execve
+ b.d ret_from_exception
+ mov sp, r0
+ARC_EXIT ret_from_kernel_execve
- b ret_from_system_call
-ARC_EXIT sys_execve_wrapper
+;################### Special Sys Call Wrappers ##########################
; TBD: call do_fork directly from here
ARC_ENTRY sys_fork_wrapper
diff --git a/arch/arc/kernel/process.c b/arch/arc/kernel/process.c
index a468205..20d8b4d 100644
--- a/arch/arc/kernel/process.c
+++ b/arch/arc/kernel/process.c
@@ -53,50 +53,6 @@ asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
child_tidptr);
}
-int sys_execve(const char __user *filenamei, const char __user *__user *argv,
- const char __user *__user *envp, struct pt_regs *regs)
-{
- long error;
- struct filename *filename;
-
- filename = getname(filenamei);
- error = PTR_ERR(filename);
- if (IS_ERR(filename))
- goto out;
-
- error = do_execve(filename->name, argv, envp, regs);
- putname(filename);
-out:
- return error;
-}
-
-int kernel_execve(const char *filename, const char *const argv[],
- const char *const envp[])
-{
- /*
- * Although the arguments (order, number) to this function are
- * same as sys call, we don't need to setup args in regs again.
- * However in case mainline kernel changes the order of args to
- * kernel_execve, that assumtion will break.
- * So to be safe, let gcc know the args for sys call.
- * If they match no extra code will be generated
- */
- register int arg2 asm("r1") = (int)argv;
- register int arg3 asm("r2") = (int)envp;
-
- register int filenm_n_ret asm("r0") = (int)filename;
-
- __asm__ __volatile__(
- "mov r8, %1 \n\t"
- "trap0 \n\t"
- : "+r"(filenm_n_ret)
- : "i"(__NR_execve), "r"(arg2), "r"(arg3)
- : "r8", "memory");
-
- return filenm_n_ret;
-}
-EXPORT_SYMBOL(kernel_execve);
-
SYSCALL_DEFINE1(arc_settls, void *, user_tls_data_ptr)
{
task_thread_info(current)->thr_ptr = (unsigned int)user_tls_data_ptr;
diff --git a/arch/arc/kernel/sys.c b/arch/arc/kernel/sys.c
index 4c30345..f6bdd07 100644
--- a/arch/arc/kernel/sys.c
+++ b/arch/arc/kernel/sys.c
@@ -5,7 +5,6 @@
#include <asm/syscalls.h>
-#define sys_execve sys_execve_wrapper
#define sys_clone sys_clone_wrapper
#define sys_fork sys_fork_wrapper
#define sys_vfork sys_vfork_wrapper
--
1.7.4.1
--
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