2006-08-30 12:53:37

by Arnd Bergmann

[permalink] [raw]
Subject: [PATCH 3/6] provide kernel_execve on all architectures

This adds the new kernel_execve function on all architectures
that were using _syscall3() to implement execve.

The implementation uses code from the _syscall3 macros provided
in the unistd.h header file. I don't have cross-compilers for
any of these architectures, so the patch is untested with the
exception of i386.

Most architectures can probably implement this in a nicer way
in assembly or by combining it with the sys_execve implementation
itself, but this should do it for now.

Signed-off-by: Arnd Bergmann <[email protected]>
Index: linux-cg/arch/h8300/kernel/sys_h8300.c
===================================================================
--- linux-cg.orig/arch/h8300/kernel/sys_h8300.c 2006-08-29 19:49:13.000000000 +0200
+++ linux-cg/arch/h8300/kernel/sys_h8300.c 2006-08-29 19:49:33.000000000 +0200
@@ -280,3 +280,26 @@
((regs->pc)&0xffffff)-2,regs->orig_er0,regs->er1,regs->er2,regs->er3,regs->er0);
}
#endif
+
+/*
+ * Do a system call from kernel instead of calling sys_execve so we
+ * end up with proper pt_regs.
+ */
+int kernel_execve(const char *filename, char *const argv[], char *const envp[])
+{
+ register long res __asm__("er0");
+ register const char * _a __asm__("er1") = filename;
+ register void *_b __asm__("er2") = argv;
+ register void *_c __asm__("er3") = envp;
+ __asm__ __volatile__ ("mov.l %1,er0\n\t"
+ "trapa #0\n\t"
+ : "=r" (res)
+ : "g" (__NR_execve),
+ "g" (_a),
+ "g" (_b),
+ "g" (_c)
+ : "cc", "memory");
+ return res;
+}
+
+
Index: linux-cg/arch/i386/kernel/sys_i386.c
===================================================================
--- linux-cg.orig/arch/i386/kernel/sys_i386.c 2006-08-29 19:49:13.000000000 +0200
+++ linux-cg/arch/i386/kernel/sys_i386.c 2006-08-29 19:49:33.000000000 +0200
@@ -243,3 +243,17 @@

return error;
}
+
+
+/*
+ * Do a system call from kernel instead of calling sys_execve so we
+ * end up with proper pt_regs.
+ */
+int kernel_execve(const char *filename, char *const argv[], char *const envp[])
+{
+ long __res;
+ asm volatile ("push %%ebx ; movl %2,%%ebx ; int $0x80 ; pop %%ebx"
+ : "=a" (__res)
+ : "0" (__NR_execve),"ri" (filename),"c" (argv), "d" (envp) : "memory");
+ return __res;
+}
Index: linux-cg/arch/m32r/kernel/sys_m32r.c
===================================================================
--- linux-cg.orig/arch/m32r/kernel/sys_m32r.c 2006-08-29 19:49:13.000000000 +0200
+++ linux-cg/arch/m32r/kernel/sys_m32r.c 2006-08-29 19:49:33.000000000 +0200
@@ -25,6 +25,8 @@
#include <asm/cachectl.h>
#include <asm/cacheflush.h>
#include <asm/ipc.h>
+#include <asm/syscall.h>
+#include <asm/unistd.h>

/*
* sys_tas() - test-and-set
@@ -223,3 +225,21 @@
return -ENOSYS;
}

+/*
+ * Do a system call from kernel instead of calling sys_execve so we
+ * end up with proper pt_regs.
+ */
+int kernel_execve(const char *filename, char *const argv[], char *const envp[])
+{
+ register long __scno __asm__ ("r7") = __NR_execve;
+ register long __arg3 __asm__ ("r2") = (long)(envp);
+ register long __arg2 __asm__ ("r1") = (long)(argv);
+ register long __res __asm__ ("r0") = (long)(filename);
+ __asm__ __volatile__ (
+ "trap #" SYSCALL_VECTOR "|| nop"
+ : "=r" (__res)
+ : "r" (__scno), "0" (__res), "r" (__arg2),
+ "r" (__arg3)
+ : "memory");
+ return __res;
+}
Index: linux-cg/arch/m68k/kernel/sys_m68k.c
===================================================================
--- linux-cg.orig/arch/m68k/kernel/sys_m68k.c 2006-08-29 19:49:13.000000000 +0200
+++ linux-cg/arch/m68k/kernel/sys_m68k.c 2006-08-29 19:49:33.000000000 +0200
@@ -663,3 +663,18 @@
{
return PAGE_SIZE;
}
+
+/*
+ * Do a system call from kernel instead of calling sys_execve so we
+ * end up with proper pt_regs.
+ */
+int kernel_execve(const char *filename, char *const argv[], char *const envp[])
+{
+ register long __res asm ("%d0") = __NR_execve;
+ register long __a asm ("%d1") = (long)(filename);
+ register long __b asm ("%d2") = (long)(argv);
+ register long __c asm ("%d3") = (long)(envp);
+ asm volatile ("trap #0" : "+d" (__res)
+ : "d" (__a), "d" (__b), "d" (__c));
+ return __res;
+}
Index: linux-cg/arch/m68knommu/kernel/sys_m68k.c
===================================================================
--- linux-cg.orig/arch/m68knommu/kernel/sys_m68k.c 2006-08-29 19:49:13.000000000 +0200
+++ linux-cg/arch/m68knommu/kernel/sys_m68k.c 2006-08-29 19:49:33.000000000 +0200
@@ -206,3 +206,17 @@
return PAGE_SIZE;
}

+/*
+ * Do a system call from kernel instead of calling sys_execve so we
+ * end up with proper pt_regs.
+ */
+int kernel_execve(const char *filename, char *const argv[], char *const envp[])
+{
+ register long __res asm ("%d0") = __NR_execve;
+ register long __a asm ("%d1") = (long)(filename);
+ register long __b asm ("%d2") = (long)(argv);
+ register long __c asm ("%d3") = (long)(envp);
+ asm volatile ("trap #0" : "+d" (__res)
+ : "d" (__a), "d" (__b), "d" (__c));
+ return __res;
+}
Index: linux-cg/arch/mips/kernel/syscall.c
===================================================================
--- linux-cg.orig/arch/mips/kernel/syscall.c 2006-08-29 19:49:13.000000000 +0200
+++ linux-cg/arch/mips/kernel/syscall.c 2006-08-29 19:49:33.000000000 +0200
@@ -399,3 +399,27 @@
{
do_exit(SIGSEGV);
}
+
+/*
+ * Do a system call from kernel instead of calling sys_execve so we
+ * end up with proper pt_regs.
+ */
+int kernel_execve(const char *filename, char *const argv[], char *const envp[])
+{
+ register unsigned long __a0 asm("$4") = (unsigned long) filename;
+ register unsigned long __a1 asm("$5") = (unsigned long) argv;
+ register unsigned long __a2 asm("$6") = (unsigned long) envp;
+ register unsigned long __a3 asm("$7");
+ unsigned long __v0;
+ __asm__ volatile (
+ ".set\tnoreorder\n\t"
+ "li\t$2, %5\t\t\t# " #name "\n\t"
+ "syscall\n\t"
+ "move\t%0, $2\n\t"
+ ".set\treorder"
+ : "=&r" (__v0), "=r" (__a3)
+ : "r" (__a0), "r" (__a1), "r" (__a2), "i" (__NR_execve)
+ : "$2", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24",
+ "memory");
+ return __v0;
+}
Index: linux-cg/arch/s390/kernel/sys_s390.c
===================================================================
--- linux-cg.orig/arch/s390/kernel/sys_s390.c 2006-08-29 19:49:13.000000000 +0200
+++ linux-cg/arch/s390/kernel/sys_s390.c 2006-08-29 19:49:33.000000000 +0200
@@ -266,3 +266,21 @@
return sys_fadvise64_64(a.fd, a.offset, a.len, a.advice);
}

+/*
+ * Do a system call from kernel instead of calling sys_execve so we
+ * end up with proper pt_regs.
+ */
+int kernel_execve(const char *filename, char *const argv[], char *const envp[])
+{
+ register const char *__arg1 asm("2") = filename;
+ register void *__arg2 asm("3") = argv;
+ register void *__arg3 asm("4") = envp;
+ register long __svcres asm("2");
+ asm volatile ("svc %b1"
+ : "=d" (__svcres)
+ : "i" (__NR_execve),
+ "0" (__arg1),
+ "d" (__arg2),
+ "d" (__arg3) : "1", "cc", "memory");
+ return __svcres;
+}
Index: linux-cg/arch/sh/kernel/sys_sh.c
===================================================================
--- linux-cg.orig/arch/sh/kernel/sys_sh.c 2006-08-29 19:49:13.000000000 +0200
+++ linux-cg/arch/sh/kernel/sys_sh.c 2006-08-29 19:49:33.000000000 +0200
@@ -295,3 +295,19 @@
(u64)len0 << 32 | len1, advice);
#endif
}
+
+/*
+ * Do a system call from kernel instead of calling sys_execve so we
+ * end up with proper pt_regs.
+ */
+int kernel_execve(const char *filename, char *const argv[], char *const envp[])
+{
+ register long __sc0 __asm__ ("r3") = __NR_execve;
+ register long __sc4 __asm__ ("r4") = (long) filename;
+ register long __sc5 __asm__ ("r5") = (long) argv;
+ register long __sc6 __asm__ ("r6") = (long) envp;
+ __asm__ __volatile__ ("trapa #0x13" : "=z" (__sc0)
+ : "0" (__sc0), "r" (__sc4), "r" (__sc5), "r" (__sc6)
+ : "memory");
+ return __sc0;
+}
Index: linux-cg/arch/sh64/kernel/sys_sh64.c
===================================================================
--- linux-cg.orig/arch/sh64/kernel/sys_sh64.c 2006-08-29 19:49:13.000000000 +0200
+++ linux-cg/arch/sh64/kernel/sys_sh64.c 2006-08-29 19:49:33.000000000 +0200
@@ -283,3 +283,21 @@
up_read(&uts_sem);
return err?-EFAULT:0;
}
+
+/*
+ * Do a system call from kernel instead of calling sys_execve so we
+ * end up with proper pt_regs.
+ */
+int kernel_execve(const char *filename, char *const argv[], char *const envp[])
+{
+ register unsigned long __sc0 __asm__ ("r9") = ((0x13 << 16) | __NR_execve);
+ register unsigned long __sc2 __asm__ ("r2") = (unsigned long) filename;
+ register unsigned long __sc3 __asm__ ("r3") = (unsigned long) argv;
+ register unsigned long __sc4 __asm__ ("r4") = (unsigned long) envp;
+ __asm__ __volatile__ ("trapa %1 !\t\t\t execve(%2,%3,%4)"
+ : "=r" (__sc0)
+ : "r" (__sc0), "r" (__sc2), "r" (__sc3), "r" (__sc4) );
+ __asm__ __volatile__ ("!dummy %0 %1 %2 %3"
+ : : "r" (__sc0), "r" (__sc2), "r" (__sc3), "r" (__sc4) : "memory");
+ return __sc0;
+}
Index: linux-cg/arch/sparc/kernel/sys_sparc.c
===================================================================
--- linux-cg.orig/arch/sparc/kernel/sys_sparc.c 2006-08-29 19:49:13.000000000 +0200
+++ linux-cg/arch/sparc/kernel/sys_sparc.c 2006-08-29 19:49:33.000000000 +0200
@@ -483,3 +483,25 @@
up_read(&uts_sem);
return err;
}
+
+/*
+ * Do a system call from kernel instead of calling sys_execve so we
+ * end up with proper pt_regs.
+ */
+int kernel_execve(const char *filename, char *const argv[], char *const envp[])
+{
+ long __res;
+ register long __g1 __asm__ ("g1") = __NR_execve;
+ register long __o0 __asm__ ("o0") = (long)(filename);
+ register long __o1 __asm__ ("o1") = (long)(argv);
+ register long __o2 __asm__ ("o2") = (long)(envp);
+ asm volatile ("t 0x10\n\t"
+ "bcc 1f\n\t"
+ "mov %%o0, %0\n\t"
+ "sub %%g0, %%o0, %0\n\t"
+ "1:\n\t"
+ : "=r" (__res), "=&r" (__o0)
+ : "1" (__o0), "r" (__o1), "r" (__o2), "r" (__g1)
+ : "cc");
+ return __res;
+}
Index: linux-cg/arch/sparc64/kernel/sys_sparc.c
===================================================================
--- linux-cg.orig/arch/sparc64/kernel/sys_sparc.c 2006-08-29 19:49:13.000000000 +0200
+++ linux-cg/arch/sparc64/kernel/sys_sparc.c 2006-08-29 19:49:33.000000000 +0200
@@ -957,3 +957,23 @@
};
return err;
}
+
+/*
+ * Do a system call from kernel instead of calling sys_execve so we
+ * end up with proper pt_regs.
+ */
+int kernel_execve(const char *filename, char *const argv[], char *const envp[])
+{
+ long __res;
+ register long __g1 __asm__ ("g1") = __NR_execve;
+ register long __o0 __asm__ ("o0") = (long)(filename);
+ register long __o1 __asm__ ("o1") = (long)(argv);
+ register long __o2 __asm__ ("o2") = (long)(envp);
+ asm volatile ("t 0x6d\n\t"
+ "sub %%g0, %%o0, %0\n\t"
+ "movcc %%xcc, %%o0, %0\n\t"
+ : "=r" (__res), "=&r" (__o0)
+ : "1" (__o0), "r" (__o1), "r" (__o2), "r" (__g1)
+ : "cc");
+ return __res;
+}
Index: linux-cg/arch/v850/kernel/syscalls.c
===================================================================
--- linux-cg.orig/arch/v850/kernel/syscalls.c 2006-08-29 19:49:13.000000000 +0200
+++ linux-cg/arch/v850/kernel/syscalls.c 2006-08-29 19:49:33.000000000 +0200
@@ -194,3 +194,22 @@
out:
return err;
}
+
+/*
+ * Do a system call from kernel instead of calling sys_execve so we
+ * end up with proper pt_regs.
+ */
+int kernel_execve(const char *filename, char *const argv[], char *const envp[])
+{
+ register char *__a __asm__ ("r6") = filename;
+ register void *__b __asm__ ("r7") = argv;
+ register void *__c __asm__ ("r8") = envp;
+ register unsigned long __syscall __asm__ ("r12") = __NR_execve;
+ register unsigned long __ret __asm__ ("r10");
+ __asm__ __volatile__ ("trap 0"
+ : "=r" (__ret), "=r" (__syscall)
+ : "1" (__syscall), "r" (__a), "r" (__b), "r" (__c)
+ : "r1", "r5", "r11", "r13", "r14",
+ "r15", "r16", "r17", "r18", "r19");
+ return __ret;
+}
Index: linux-cg/arch/xtensa/kernel/syscalls.c
===================================================================
--- linux-cg.orig/arch/xtensa/kernel/syscalls.c 2006-08-29 19:49:13.000000000 +0200
+++ linux-cg/arch/xtensa/kernel/syscalls.c 2006-08-29 19:49:33.000000000 +0200
@@ -266,3 +266,23 @@
regs->areg[2] = res;
do_syscall_trace();
}
+
+/*
+ * Do a system call from kernel instead of calling sys_execve so we
+ * end up with proper pt_regs.
+ */
+int kernel_execve(const char *filename, char *const argv[], char *const envp[])
+{
+ long __res;
+ asm volatile (
+ " mov a5, %2 \n"
+ " mov a4, %4 \n"
+ " mov a3, %3 \n"
+ " movi a2, %1 \n"
+ " syscall \n"
+ " mov %0, a2 \n"
+ : "=a" (__res)
+ : "i" (__NR_execve), "a" (filename), "a" (argv), "a" (envp)
+ : "a2", "a3", "a4", "a5");
+ return __res;
+}
Index: linux-cg/arch/frv/kernel/Makefile
===================================================================
--- linux-cg.orig/arch/frv/kernel/Makefile 2006-04-02 23:16:53.000000000 +0200
+++ linux-cg/arch/frv/kernel/Makefile 2006-08-29 20:02:13.000000000 +0200
@@ -8,7 +8,7 @@
extra-y:= head.o init_task.o vmlinux.lds

obj-y := $(heads-y) entry.o entry-table.o break.o switch_to.o kernel_thread.o \
- process.o traps.o ptrace.o signal.o dma.o \
+ kernel_execve.o process.o traps.o ptrace.o signal.o dma.o \
sys_frv.o time.o semaphore.o setup.o frv_ksyms.o \
debug-stub.o irq.o irq-routing.o sleep.o uaccess.o

Index: linux-cg/arch/frv/kernel/kernel_execve.S
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-cg/arch/frv/kernel/kernel_execve.S 2006-08-29 20:02:13.000000000 +0200
@@ -0,0 +1,33 @@
+/* in-kernel program execution
+ *
+ * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells ([email protected])
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/linkage.h>
+#include <asm/unistd.h>
+
+###############################################################################
+#
+# Do a system call from kernel instead of calling sys_execve so we end up with
+# proper pt_regs.
+#
+# int kernel_execve(const char *filename, char *const argv[], char *const envp[])
+#
+# On entry: GR8/GR9/GR10: arguments to function
+# On return: GR8: syscall return.
+#
+###############################################################################
+ .globl kernel_execve
+ .type kernel_execve,@function
+kernel_execve:
+ setlos __NR_execve,gr7
+ tira gr0,#0
+ bralr
+
+ .size kernel_execve,.-kernel_execve

--


2006-08-30 14:16:43

by Martin Schwidefsky

[permalink] [raw]
Subject: Re: [PATCH 3/6] provide kernel_execve on all architectures

On Wed, 2006-08-30 at 14:43 +0200, Arnd Bergmann wrote:
> This adds the new kernel_execve function on all architectures
> that were using _syscall3() to implement execve.

Doesn't compile for s390. Patch attached, issues fixed:
1) Include unistd.h for __NR_execve
2) The compiler warns about __arg2 and __arg3 assignments (watch out for
the *const* - isn't C a lovely language ;-)
3) The inline assembly does not clobber register "1", nor the condition
code. The call to kernel_execve does clobber both so it is not really a
problem, but nit-picking is fun >:-)

--
blue skies,
Martin.

Martin Schwidefsky
Linux for zSeries Development & Services
IBM Deutschland Entwicklung GmbH

"Reality continues to ruin my life." - Calvin.

---
diff -urpN linux-2.6/arch/s390/kernel/sys_s390.c linux-2.6-patched/arch/s390/kernel/sys_s390.c
--- linux-2.6/arch/s390/kernel/sys_s390.c 2006-08-30 15:23:14.000000000 +0200
+++ linux-2.6-patched/arch/s390/kernel/sys_s390.c 2006-08-30 15:18:37.000000000 +0200
@@ -27,6 +27,7 @@
#include <linux/file.h>
#include <linux/utsname.h>
#include <linux/personality.h>
+#include <linux/unistd.h>

#include <asm/uaccess.h>
#include <asm/ipc.h>
@@ -273,14 +274,15 @@ s390_fadvise64_64(struct fadvise64_64_ar
int kernel_execve(const char *filename, char *const argv[], char *const envp[])
{
register const char *__arg1 asm("2") = filename;
- register void *__arg2 asm("3") = argv;
- register void *__arg3 asm("4") = envp;
+ register char *const*__arg2 asm("3") = argv;
+ register char *const*__arg3 asm("4") = envp;
register long __svcres asm("2");
- asm volatile ("svc %b1"
+ asm volatile(
+ "svc %b1"
: "=d" (__svcres)
: "i" (__NR_execve),
"0" (__arg1),
"d" (__arg2),
- "d" (__arg3) : "1", "cc", "memory");
+ "d" (__arg3) : "memory");
return __svcres;
}