uml: more page fault path trimming

More trimming of the page fault path.

Permissions are passed around in a single int rather than one bit per
int.  The permission values are copied from libc so that they can be
passed to mmap and mprotect without any further conversion.

The register sets used by do_syscall_stub and copy_context_skas0 are
initialized once, at boot time, rather than once per call.

wait_stub_done checks whether it is getting the signals it expects by
comparing the wait status to a mask containing bits for the signals of
interest rather than comparing individually to the signal numbers.  It
also has one check for a wait failure instead of two.  The caller is
expected to do the initial continue of the stub.  This gets rid of an
argument and some logic.  The fname argument is gone, as that can be
had from a stack trace.

user_signal() is collapsed into userspace() as it is basically one or
two lines of code afterwards.

The physical memory remapping stuff is gone, as it is unused.

flush_tlb_page is inlined.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 14 insertions, 28 deletions

diff --git a/arch/um/kernel/tlb.c b/arch/um/kernel/tlb.c
index 4a39d50d2d62..8a8d52851443 100644
--- a/arch/um/kernel/tlb.c
+++ b/arch/um/kernel/tlb.c
@@ -17,7 +17,7 @@
 #include "os.h"
 
 static int add_mmap(unsigned long virt, unsigned long phys, unsigned long len,
-                    int r, int w, int x, struct host_vm_op *ops, int *index,
+                    unsigned int prot, struct host_vm_op *ops, int *index,
                     int last_filled, union mm_context *mmu, void **flush,
                     int (*do_ops)(union mm_context *, struct host_vm_op *,
                                   int, int, void **))
@@ -31,8 +31,7 @@ static int add_mmap(unsigned long virt, unsigned long phys, unsigned long len,
                 last = &ops[*index];
                 if((last->type == MMAP) &&
                    (last->u.mmap.addr + last->u.mmap.len == virt) &&
-                   (last->u.mmap.r == r) && (last->u.mmap.w == w) &&
-                   (last->u.mmap.x == x) && (last->u.mmap.fd == fd) &&
+                   (last->u.mmap.prot == prot) && (last->u.mmap.fd == fd) &&
                    (last->u.mmap.offset + last->u.mmap.len == offset)){
                         last->u.mmap.len += len;
                         return 0;
@@ -48,9 +47,7 @@ static int add_mmap(unsigned long virt, unsigned long phys, unsigned long len,
                                                 .u = { .mmap = {
                                                        .addr    = virt,
                                                        .len     = len,
-                                                       .r       = r,
-                                                       .w       = w,
-                                                       .x       = x,
+                                                       .prot    = prot,
                                                        .fd      = fd,
                                                        .offset  = offset }
                            } });
@@ -87,8 +84,8 @@ static int add_munmap(unsigned long addr, unsigned long len,
         return ret;
 }
 
-static int add_mprotect(unsigned long addr, unsigned long len, int r, int w,
-                        int x, struct host_vm_op *ops, int *index,
+static int add_mprotect(unsigned long addr, unsigned long len,
+                        unsigned int prot, struct host_vm_op *ops, int *index,
                         int last_filled, union mm_context *mmu, void **flush,
                         int (*do_ops)(union mm_context *, struct host_vm_op *,
                                       int, int, void **))
@@ -100,8 +97,7 @@ static int add_mprotect(unsigned long addr, unsigned long len, int r, int w,
                 last = &ops[*index];
                 if((last->type == MPROTECT) &&
                    (last->u.mprotect.addr + last->u.mprotect.len == addr) &&
-                   (last->u.mprotect.r == r) && (last->u.mprotect.w == w) &&
-                   (last->u.mprotect.x == x)){
+                   (last->u.mprotect.prot == prot)){
                         last->u.mprotect.len += len;
                         return 0;
                 }
@@ -116,9 +112,7 @@ static int add_mprotect(unsigned long addr, unsigned long len, int r, int w,
                                                .u = { .mprotect = {
                                                        .addr    = addr,
                                                        .len     = len,
-                                                       .r       = r,
-                                                       .w       = w,
-                                                       .x       = x } } });
+                                                       .prot    = prot } } });
         return ret;
 }
 
@@ -133,7 +127,7 @@ static inline int update_pte_range(pmd_t *pmd, unsigned long addr,
                                                  void **))
 {
         pte_t *pte;
-        int r, w, x, ret = 0;
+        int r, w, x, prot, ret = 0;
 
         pte = pte_offset_kernel(pmd, addr);
         do {
@@ -146,19 +140,19 @@ static inline int update_pte_range(pmd_t *pmd, unsigned long addr,
                 } else if (!pte_dirty(*pte)) {
                         w = 0;
                 }
+                prot = ((r ? UM_PROT_READ : 0) | (w ? UM_PROT_WRITE : 0) |
+                        (x ? UM_PROT_EXEC : 0));
                 if(force || pte_newpage(*pte)){
                         if(pte_present(*pte))
                                 ret = add_mmap(addr, pte_val(*pte) & PAGE_MASK,
-                                               PAGE_SIZE, r, w, x, ops,
-                                               op_index, last_op, mmu, flush,
-                                               do_ops);
+                                               PAGE_SIZE, prot, ops, op_index,
+                                               last_op, mmu, flush, do_ops);
                         else ret = add_munmap(addr, PAGE_SIZE, ops, op_index,
                                               last_op, mmu, flush, do_ops);
                 }
                 else if(pte_newprot(*pte))
-                        ret = add_mprotect(addr, PAGE_SIZE, r, w, x, ops,
-                                           op_index, last_op, mmu, flush,
-                                           do_ops);
+                        ret = add_mprotect(addr, PAGE_SIZE, prot, ops, op_index,
+                                           last_op, mmu, flush, do_ops);
                 *pte = pte_mkuptodate(*pte);
         } while (pte++, addr += PAGE_SIZE, ((addr != end) && !ret));
         return ret;
@@ -377,14 +371,6 @@ pte_t *addr_pte(struct task_struct *task, unsigned long addr)
         return(pte_offset_map(pmd, addr));
 }
 
-void flush_tlb_page(struct vm_area_struct *vma, unsigned long address)
-{
-        address &= PAGE_MASK;
-
-        CHOOSE_MODE(flush_tlb_range(vma, address, address + PAGE_SIZE),
-                    flush_tlb_page_skas(vma, address));
-}
-
 void flush_tlb_all(void)
 {
         flush_tlb_mm(current->mm);