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Message-ID: <20080425175606.GA11174@c2.user-mode-linux.org>
Date: Fri, 25 Apr 2008 13:56:06 -0400
From: Jeff Dike <jdike@...toit.com>
To: Andrew Morton <akpm@...l.org>, LKML <linux-kernel@...r.kernel.org>,
uml-devel <user-mode-linux-devel@...ts.sourceforge.net>
Subject: [PATCH 2/19] UML - Tidy stub management code
Restructure the stub management code to make it simpler.
syscall_stub_done is extracted from do_syscall_stub.
The counters are gone since I never looked at them.
The common code in run_syscall_stub and syscall_stub_data is extracted
into flush_syscalls.
Signed-off-by: Jeff Dike <jdike@...ux.intel.com>
---
arch/um/os-Linux/skas/mem.c | 162 +++++++++++++++++++++++---------------------
1 file changed, 85 insertions(+), 77 deletions(-)
Index: linux-2.6-git/arch/um/os-Linux/skas/mem.c
===================================================================
--- linux-2.6-git.orig/arch/um/os-Linux/skas/mem.c 2008-04-25 11:36:59.000000000 -0400
+++ linux-2.6-git/arch/um/os-Linux/skas/mem.c 2008-04-25 11:39:07.000000000 -0400
@@ -40,35 +40,69 @@ static unsigned long syscall_regs[MAX_RE
static int __init init_syscall_regs(void)
{
+ unsigned long *stub_entry;
+
get_safe_registers(syscall_regs);
+ stub_entry = &batch_syscall_stub;
+
syscall_regs[REGS_IP_INDEX] = STUB_CODE +
- ((unsigned long) &batch_syscall_stub -
+ ((unsigned long) stub_entry -
(unsigned long) &__syscall_stub_start);
return 0;
}
__initcall(init_syscall_regs);
-extern int proc_mm;
+static int syscall_stub_done(unsigned long stack)
+{
+ unsigned long *syscall, *data, offset;
+ int ret, n;
+
+ /*
+ * When the stub stops, we find the following values on the
+ * beginning of the stack:
+ * (long) return_value
+ * (long) offset to failed sycall data (0 if no error)
+ */
+ ret = *((unsigned long *) stack);
+ offset = *((unsigned long *) stack + 1);
+ if (offset == 0)
+ return 0;
-int single_count = 0;
-int multi_count = 0;
-int multi_op_count = 0;
+ data = (unsigned long *)(stack + offset - STUB_DATA);
+ printk(UM_KERN_ERR "syscall_stub_done : ret = %d, offset = %ld, "
+ "data = %p\n", ret, offset, data);
+ syscall = (unsigned long *)((unsigned long)data + data[0]);
+ printk(UM_KERN_ERR "syscall_stub_done : syscall %ld failed, "
+ "return value = 0x%x, expected return value = 0x%lx\n",
+ syscall[0], ret, syscall[7]);
+ printk(UM_KERN_ERR " syscall parameters: "
+ "0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
+ syscall[1], syscall[2], syscall[3],
+ syscall[4], syscall[5], syscall[6]);
+ for (n = 1; n < data[0]/sizeof(long); n++) {
+ if (n == 1)
+ printk(UM_KERN_ERR " additional syscall "
+ "data:");
+ if (n % 4 == 1)
+ printk(UM_KERN_CONT "\n" UM_KERN_ERR " ");
+ printk(UM_KERN_CONT " 0x%lx", data[n]);
+ }
+ if (n > 1)
+ printk("\n");
-static inline long do_syscall_stub(struct mm_id * mm_idp, void **addr)
+ return ret;
+}
+
+static long do_syscall_stub(struct mm_id *mm_idp, void **addr)
{
- int n, i;
- long ret, offset;
- unsigned long * data;
- unsigned long * syscall;
- int err, pid = mm_idp->u.pid;
+ long ret;
+ int n, i, err, pid = mm_idp->u.pid;
if (proc_mm)
/* FIXME: Need to look up userspace_pid by cpu */
pid = userspace_pid[0];
- multi_count++;
-
n = ptrace_setregs(pid, syscall_regs);
if (n < 0) {
printk(UM_KERN_ERR "Registers - \n");
@@ -85,52 +119,39 @@ static inline long do_syscall_stub(struc
wait_stub_done(pid);
- /*
- * When the stub stops, we find the following values on the
- * beginning of the stack:
- * (long )return_value
- * (long )offset to failed sycall-data (0, if no error)
- */
- ret = *((unsigned long *) mm_idp->stack);
- offset = *((unsigned long *) mm_idp->stack + 1);
- if (offset) {
- data = (unsigned long *)(mm_idp->stack + offset - STUB_DATA);
- printk(UM_KERN_ERR "do_syscall_stub : ret = %ld, offset = %ld, "
- "data = %p\n", ret, offset, data);
- syscall = (unsigned long *)((unsigned long)data + data[0]);
- printk(UM_KERN_ERR "do_syscall_stub: syscall %ld failed, "
- "return value = 0x%lx, expected return value = 0x%lx\n",
- syscall[0], ret, syscall[7]);
- printk(UM_KERN_ERR " syscall parameters: "
- "0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
- syscall[1], syscall[2], syscall[3],
- syscall[4], syscall[5], syscall[6]);
- for (n = 1; n < data[0]/sizeof(long); n++) {
- if (n == 1)
- printk(UM_KERN_ERR " additional syscall "
- "data:");
- if (n % 4 == 1)
- printk("\n" UM_KERN_ERR " ");
- printk(" 0x%lx", data[n]);
- }
- if (n > 1)
- printk("\n");
- }
- else ret = 0;
+ ret = syscall_stub_done(mm_idp->stack);
*addr = check_init_stack(mm_idp, NULL);
return ret;
}
-long run_syscall_stub(struct mm_id * mm_idp, int syscall,
+static int flush_syscalls(struct mm_id *mm_idp, void **addr, int extra)
+{
+ unsigned long *stack = check_init_stack(mm_idp, *addr);
+ int current, end;
+
+ current = ((unsigned long) stack) & ~UM_KERN_PAGE_MASK;
+ end = UM_KERN_PAGE_SIZE;
+
+ if (current + (10 + extra) * sizeof(long) < end)
+ return 0;
+
+ return do_syscall_stub(mm_idp, addr);
+}
+
+long run_syscall_stub(struct mm_id *mm_idp, int syscall,
unsigned long *args, long expected, void **addr,
int done)
{
- unsigned long *stack = check_init_stack(mm_idp, *addr);
+ unsigned long *stack;
+ int ret;
- if (done && *addr == NULL)
- single_count++;
+ ret = flush_syscalls(mm_idp, addr, 0);
+ if (ret)
+ return ret;
+
+ stack = check_init_stack(mm_idp, *addr);
*stack += sizeof(long);
stack += *stack / sizeof(long);
@@ -144,45 +165,32 @@ long run_syscall_stub(struct mm_id * mm_
*stack++ = args[5];
*stack++ = expected;
*stack = 0;
- multi_op_count++;
- if (!done && ((((unsigned long) stack) & ~UM_KERN_PAGE_MASK) <
- UM_KERN_PAGE_SIZE - 10 * sizeof(long))) {
- *addr = stack;
- return 0;
- }
+ if (done)
+ return do_syscall_stub(mm_idp, addr);
- return do_syscall_stub(mm_idp, addr);
+ *addr = stack;
+
+ return 0;
}
-long syscall_stub_data(struct mm_id * mm_idp,
- unsigned long *data, int data_count,
- void **addr, void **stub_addr)
+long syscall_stub_data(struct mm_id *mm_idp, unsigned long *data,
+ int data_count, void **addr, void **stub_addr)
{
unsigned long *stack;
- int ret = 0;
+ int ret;
- /*
- * If *addr still is uninitialized, it *must* contain NULL.
- * Thus in this case do_syscall_stub correctly won't be called.
- */
- if ((((unsigned long) *addr) & ~UM_KERN_PAGE_MASK) >=
- UM_KERN_PAGE_SIZE - (10 + data_count) * sizeof(long)) {
- ret = do_syscall_stub(mm_idp, addr);
- /* in case of error, don't overwrite data on stack */
- if (ret)
- return ret;
- }
+ ret = flush_syscalls(mm_idp, addr, data_count);
+ if (ret)
+ return ret;
stack = check_init_stack(mm_idp, *addr);
- *addr = stack;
-
- *stack = data_count * sizeof(long);
+ *stack++ = data_count * sizeof(long);
- memcpy(stack + 1, data, data_count * sizeof(long));
+ memcpy(stack, data, data_count * sizeof(long));
- *stub_addr = (void *)(((unsigned long)(stack + 1) &
- ~UM_KERN_PAGE_MASK) + STUB_DATA);
+ *stub_addr = (void *)(((unsigned long) stack & ~UM_KERN_PAGE_MASK) +
+ STUB_DATA);
return 0;
}
--
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