From: Paolo 'Blaisorblade' Giarrusso <[email protected]>
Avoid chomping low bits of address for functions doing it by themselves, fix
whitespace, add a correctness checking.
I did this for remap-file-pages protection support, it was useful on its own
too.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <[email protected]>
---
linux-2.6.git-paolo/arch/um/kernel/trap_kern.c | 28 +++++++++++--------------
1 files changed, 13 insertions(+), 15 deletions(-)
diff -puN arch/um/kernel/trap_kern.c~uml-fault-handler-changes arch/um/kernel/trap_kern.c
--- linux-2.6.git/arch/um/kernel/trap_kern.c~uml-fault-handler-changes 2005-08-11 11:18:03.000000000 +0200
+++ linux-2.6.git-paolo/arch/um/kernel/trap_kern.c 2005-08-11 11:19:56.000000000 +0200
@@ -26,6 +26,7 @@
#include "mem.h"
#include "mem_kern.h"
+/* Note this is constrained to return 0, -EFAULT, -EACCESS, -ENOMEM by segv(). */
int handle_page_fault(unsigned long address, unsigned long ip,
int is_write, int is_user, int *code_out)
{
@@ -35,7 +36,6 @@ int handle_page_fault(unsigned long addr
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
- unsigned long page;
int err = -EFAULT;
*code_out = SEGV_MAPERR;
@@ -52,7 +52,7 @@ int handle_page_fault(unsigned long addr
else if(expand_stack(vma, address))
goto out;
- good_area:
+good_area:
*code_out = SEGV_ACCERR;
if(is_write && !(vma->vm_flags & VM_WRITE))
goto out;
@@ -60,9 +60,8 @@ int handle_page_fault(unsigned long addr
if(!(vma->vm_flags & (VM_READ | VM_EXEC)))
goto out;
- page = address & PAGE_MASK;
do {
- survive:
+survive:
switch (handle_mm_fault(mm, vma, address, is_write)){
case VM_FAULT_MINOR:
current->min_flt++;
@@ -79,16 +78,16 @@ int handle_page_fault(unsigned long addr
default:
BUG();
}
- pgd = pgd_offset(mm, page);
- pud = pud_offset(pgd, page);
- pmd = pmd_offset(pud, page);
- pte = pte_offset_kernel(pmd, page);
+ pgd = pgd_offset(mm, address);
+ pud = pud_offset(pgd, address);
+ pmd = pmd_offset(pud, address);
+ pte = pte_offset_kernel(pmd, address);
} while(!pte_present(*pte));
err = 0;
*pte = pte_mkyoung(*pte);
if(pte_write(*pte)) *pte = pte_mkdirty(*pte);
- flush_tlb_page(vma, page);
- out:
+ flush_tlb_page(vma, address);
+out:
up_read(&mm->mmap_sem);
return(err);
@@ -144,19 +143,18 @@ unsigned long segv(struct faultinfo fi,
panic("Kernel mode fault at addr 0x%lx, ip 0x%lx",
address, ip);
- if(err == -EACCES){
+ if (err == -EACCES) {
si.si_signo = SIGBUS;
si.si_errno = 0;
si.si_code = BUS_ADRERR;
si.si_addr = (void *)address;
current->thread.arch.faultinfo = fi;
force_sig_info(SIGBUS, &si, current);
- }
- else if(err == -ENOMEM){
+ } else if (err == -ENOMEM) {
printk("VM: killing process %s\n", current->comm);
do_exit(SIGKILL);
- }
- else {
+ } else {
+ BUG_ON(err != -EFAULT);
si.si_signo = SIGSEGV;
si.si_addr = (void *) address;
current->thread.arch.faultinfo = fi;
_
-
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