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authorJeff Dike <jdike@addtoit.com>2008-02-04 22:31:07 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-05 09:44:29 -0800
commit8efa3c9d545ab6adc5c5e001cbd7aee60909b3da (patch)
tree1ec5750233c242168f17a9669ff4ba4aa113a2e6 /arch/um/kernel
parent0b4e273fb83bce5dd8e166a4defb16ebdd215abf (diff)
uml: eliminate setjmp_wrapper
setjmp_wrapper existed to provide setjmp to kernel code when UML used libc's setjmp and longjmp. Now that UML has its own implementation, this isn't needed and kernel code can invoke setjmp directly. do_buffer_op is massively cleaned up since it is no longer a callback from setjmp_wrapper and given a va_list from which it must extract its arguments. The actual setjmp is moved from buffer_op to do_op_one_page because the copy operation is inside an atomic section (kmap_atomic to kunmap_atomic) and it shouldn't be longjmp-ed out of. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/um/kernel')
-rw-r--r--arch/um/kernel/skas/uaccess.c73
1 files changed, 27 insertions, 46 deletions
diff --git a/arch/um/kernel/skas/uaccess.c b/arch/um/kernel/skas/uaccess.c
index 05b41dbc1dd..e22c96993db 100644
--- a/arch/um/kernel/skas/uaccess.c
+++ b/arch/um/kernel/skas/uaccess.c
@@ -58,9 +58,10 @@ static pte_t *maybe_map(unsigned long virt, int is_write)
static int do_op_one_page(unsigned long addr, int len, int is_write,
int (*op)(unsigned long addr, int len, void *arg), void *arg)
{
+ jmp_buf buf;
struct page *page;
pte_t *pte;
- int n;
+ int n, faulted;
pte = maybe_map(addr, is_write);
if (pte == NULL)
@@ -70,82 +71,62 @@ static int do_op_one_page(unsigned long addr, int len, int is_write,
addr = (unsigned long) kmap_atomic(page, KM_UML_USERCOPY) +
(addr & ~PAGE_MASK);
- n = (*op)(addr, len, arg);
+ current->thread.fault_catcher = &buf;
+
+ faulted = UML_SETJMP(&buf);
+ if (faulted == 0)
+ n = (*op)(addr, len, arg);
+ else
+ n = -1;
+
+ current->thread.fault_catcher = NULL;
kunmap_atomic(page, KM_UML_USERCOPY);
return n;
}
-static void do_buffer_op(void *jmpbuf, void *arg_ptr)
+static int buffer_op(unsigned long addr, int len, int is_write,
+ int (*op)(unsigned long, int, void *), void *arg)
{
- va_list args;
- unsigned long addr;
- int len, is_write, size, remain, n;
- int (*op)(unsigned long, int, void *);
- void *arg;
- int *res;
-
- va_copy(args, *(va_list *)arg_ptr);
- addr = va_arg(args, unsigned long);
- len = va_arg(args, int);
- is_write = va_arg(args, int);
- op = va_arg(args, void *);
- arg = va_arg(args, void *);
- res = va_arg(args, int *);
- va_end(args);
+ int size, remain, n;
+
size = min(PAGE_ALIGN(addr) - addr, (unsigned long) len);
remain = len;
- current->thread.fault_catcher = jmpbuf;
n = do_op_one_page(addr, size, is_write, op, arg);
if (n != 0) {
- *res = (n < 0 ? remain : 0);
+ remain = (n < 0 ? remain : 0);
goto out;
}
addr += size;
remain -= size;
- if (remain == 0) {
- *res = 0;
+ if (remain == 0)
goto out;
- }
- while(addr < ((addr + remain) & PAGE_MASK)) {
+ while (addr < ((addr + remain) & PAGE_MASK)) {
n = do_op_one_page(addr, PAGE_SIZE, is_write, op, arg);
if (n != 0) {
- *res = (n < 0 ? remain : 0);
+ remain = (n < 0 ? remain : 0);
goto out;
}
addr += PAGE_SIZE;
remain -= PAGE_SIZE;
}
- if (remain == 0) {
- *res = 0;
+ if (remain == 0)
goto out;
- }
n = do_op_one_page(addr, remain, is_write, op, arg);
- if (n != 0)
- *res = (n < 0 ? remain : 0);
- else *res = 0;
- out:
- current->thread.fault_catcher = NULL;
-}
-
-static int buffer_op(unsigned long addr, int len, int is_write,
- int (*op)(unsigned long addr, int len, void *arg),
- void *arg)
-{
- int faulted, res;
-
- faulted = setjmp_wrapper(do_buffer_op, addr, len, is_write, op, arg,
- &res);
- if (!faulted)
- return res;
+ if (n != 0) {
+ remain = (n < 0 ? remain : 0);
+ goto out;
+ }
- return addr + len - (unsigned long) current->thread.fault_addr;
+ return 0;
+ out:
+ return remain;
}
static int copy_chunk_from_user(unsigned long from, int len, void *arg)