[PATCHv4 2/6] x86&x86-64 support for sys_indirect

[Ulrich Drepper <drepper@redhat.com>]

This part adds support for sys_indirect on x86 and x86-64.

 arch/x86/ia32/ia32entry.S          |    2 ++
 arch/x86/ia32/sys_ia32.c           |   31 +++++++++++++++++++++++++++++++
 arch/x86/kernel/syscall_table_32.S |    1 +
 include/asm-x86/indirect.h         |    5 +++++
 include/asm-x86/indirect_32.h      |   23 +++++++++++++++++++++++
 include/asm-x86/indirect_64.h      |   34 ++++++++++++++++++++++++++++++++++
 include/asm-x86/unistd_32.h        |    3 ++-
 include/asm-x86/unistd_64.h        |    2 ++
 8 files changed, 100 insertions(+), 1 deletion(-)

--- arch/x86/ia32/ia32entry.S
+++ arch/x86/ia32/ia32entry.S
@@ -400,6 +400,7 @@ END(ia32_ptregs_common)
 
 	.section .rodata,"a"
 	.align 8
+	.globl ia32_sys_call_table
 ia32_sys_call_table:
 	.quad sys_restart_syscall
 	.quad sys_exit
@@ -726,4 +727,5 @@ ia32_sys_call_table:
 	.quad compat_sys_timerfd
 	.quad sys_eventfd
 	.quad sys32_fallocate
+	.quad sys32_indirect		/* 325  */
 ia32_syscall_end:
--- arch/x86/ia32/sys_ia32.c
+++ arch/x86/ia32/sys_ia32.c
@@ -887,3 +887,37 @@ asmlinkage long sys32_fallocate(int fd, int mode, unsigned offset_lo,
 	return sys_fallocate(fd, mode, ((u64)offset_hi << 32) | offset_lo,
 			     ((u64)len_hi << 32) | len_lo);
 }
+
+asmlinkage long sys32_indirect(struct indirect_registers32 __user *userregs,
+			       void __user *userparams, size_t paramslen,
+			       int flags)
+{
+	extern long (*ia32_sys_call_table[])(u32, u32, u32, u32, u32, u32);
+
+	struct indirect_registers32 regs;
+	long result;
+
+	if (flags != 0)
+		return -EINVAL;
+
+	if (copy_from_user(&regs, userregs, sizeof(regs)))
+		return -EFAULT;
+
+	switch (INDIRECT_SYSCALL32(&regs))
+	{
+	default:
+		return -EINVAL;
+	}
+
+	if (paramslen > sizeof(union indirect_params))
+		return -EINVAL;
+	result = -EFAULT;
+	if (!copy_from_user(&current->indirect_params, userparams, paramslen))
+		result = ia32_sys_call_table[regs.eax](regs.ebx, regs.ecx,
+						       regs.edx, regs.esi,
+						       regs.edi, regs.ebp);
+
+	memset(&current->indirect_params, '\0', paramslen);
+
+	return result;
+}
--- arch/x86/kernel/syscall_table_32.S
+++ arch/x86/kernel/syscall_table_32.S
@@ -324,3 +324,4 @@ ENTRY(sys_call_table)
 	.long sys_timerfd
 	.long sys_eventfd
 	.long sys_fallocate
+	.long sys_indirect		/* 325 */
--- /dev/null
+++ include/asm-x86/indirect_32.h
@@ -0,0 +1,23 @@
+#ifndef _ASM_X86_INDIRECT_32_H
+#define _ASM_X86_INDIRECT_32_H
+
+struct indirect_registers {
+	__u32 eax;
+	__u32 ebx;
+	__u32 ecx;
+	__u32 edx;
+	__u32 esi;
+	__u32 edi;
+	__u32 ebp;
+};
+
+#define INDIRECT_SYSCALL(regs) (regs)->eax
+
+#define CALL_INDIRECT(regs) \
+  ({ extern long (*sys_call_table[]) (__u32, __u32, __u32, __u32, __u32, __u32); \
+     sys_call_table[INDIRECT_SYSCALL(regs)] ((regs)->ebx, (regs)->ecx, \
+					     (regs)->edx, (regs)->esi, \
+					     (regs)->edi, (regs)->ebp); \
+     })
+
+#endif
--- /dev/null
+++ include/asm-x86/indirect_64.h
@@ -0,0 +1,34 @@
+#ifndef _ASM_X86_INDIRECT_64_H
+#define _ASM_X86_INDIRECT_64_H
+
+struct indirect_registers {
+	__u64 rax;
+	__u64 rdi;
+	__u64 rsi;
+	__u64 rdx;
+	__u64 r10;
+	__u64 r8;
+	__u64 r9;
+};
+
+struct indirect_registers32 {
+	__u32 eax;
+	__u32 ebx;
+	__u32 ecx;
+	__u32 edx;
+	__u32 esi;
+	__u32 edi;
+	__u32 ebp;
+};
+
+#define INDIRECT_SYSCALL(regs) (regs)->rax
+#define INDIRECT_SYSCALL32(regs) (regs)->eax
+
+#define CALL_INDIRECT(regs) \
+  ({ extern long (*sys_call_table[]) (__u64, __u64, __u64, __u64, __u64, __u64); \
+     sys_call_table[INDIRECT_SYSCALL(regs)] ((regs)->rdi, (regs)->rsi, \
+					     (regs)->rdx, (regs)->r10, \
+					     (regs)->r8, (regs)->r9); \
+     })
+
+#endif
--- /dev/null
+++ include/asm-x86/indirect.h
@@ -0,0 +1,5 @@
+#ifdef CONFIG_X86_32
+# include "indirect_32.h"
+#else
+# include "indirect_64.h"
+#endif
--- include/asm-x86/unistd_32.h
+++ include/asm-x86/unistd_32.h
@@ -330,10 +330,11 @@
 #define __NR_timerfd		322
 #define __NR_eventfd		323
 #define __NR_fallocate		324
+#define __NR_indirect		325
 
 #ifdef __KERNEL__
 
-#define NR_syscalls 325
+#define NR_syscalls 326
 
 #define __ARCH_WANT_IPC_PARSE_VERSION
 #define __ARCH_WANT_OLD_READDIR
--- include/asm-x86/unistd_64.h
+++ include/asm-x86/unistd_64.h
@@ -635,6 +635,8 @@ __SYSCALL(__NR_timerfd, sys_timerfd)
 __SYSCALL(__NR_eventfd, sys_eventfd)
 #define __NR_fallocate				285
 __SYSCALL(__NR_fallocate, sys_fallocate)
+#define __NR_indirect				286
+__SYSCALL(__NR_indirect, sys_indirect)
 
 #ifndef __NO_STUBS
 #define __ARCH_WANT_OLD_READDIR