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| author |   Zachary Amsden <zach@vmware.com> | 2005-09-03 15:56:43 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@evo.osdl.org> | 2005-09-05 00:06:12 -0700 |
| commit | 0998e4228aca046fbd747c3fed909791d52e88eb (patch) | |
| tree | 314cb04a6223100bf468cc420985bfe7e3680d44 /arch/i386/kernel | |
| parent | [PATCH] x86: more asm cleanups (diff) | |
| download | linux-dev-0998e4228aca046fbd747c3fed909791d52e88eb.tar.xz linux-dev-0998e4228aca046fbd747c3fed909791d52e88eb.zip | |
[PATCH] x86: privilege cleanup
Privilege checking cleanup. Originally, these diffs were much greater, but
recent cleanups in Linux have already done much of the cleanup. I added
some explanatory comments in places where the reasoning behind certain
tests is rather subtle.
Also, in traps.c, we can skip the user_mode check in handle_BUG(). The
reason is, there are only two call chains - one via die_if_kernel() and one
via do_page_fault(), both entering from die(). Both of these paths already
ensure that a kernel mode failure has happened. Also, the original check
here, if (user_mode(regs)) was insufficient anyways, since it would not
rule out BUG faults from V8086 mode execution.
Saving the %ss segment in show_regs() rather than assuming a fixed value
also gives better information about the current kernel state in the
register dump.
Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/i386/kernel')
| -rw-r--r-- | arch/i386/kernel/signal.c | 4 | ||||
| -rw-r--r-- | arch/i386/kernel/traps.c | 5 |
2 files changed, 4 insertions, 5 deletions
diff --git a/arch/i386/kernel/signal.c b/arch/i386/kernel/signal.c index 7bcda6d69d87..61eb0c8a6e47 100644 --- a/arch/i386/kernel/signal.c +++ b/arch/i386/kernel/signal.c @@ -604,7 +604,9 @@ int fastcall do_signal(struct pt_regs *regs, sigset_t *oldset) * We want the common case to go fast, which * is why we may in certain cases get here from * kernel mode. Just return without doing anything - * if so. + * if so. vm86 regs switched out by assembly code + * before reaching here, so testing against kernel + * CS suffices. */ if (!user_mode(regs)) return 1; diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c index 1144df0c48d6..b2b4bb890bb7 100644 --- a/arch/i386/kernel/traps.c +++ b/arch/i386/kernel/traps.c @@ -210,7 +210,7 @@ void show_registers(struct pt_regs *regs) unsigned short ss; esp = (unsigned long) (®s->esp); - ss = __KERNEL_DS; + savesegment(ss, ss); if (user_mode(regs)) { in_kernel = 0; esp = regs->esp; @@ -267,9 +267,6 @@ static void handle_BUG(struct pt_regs *regs) char c; unsigned long eip; - if (user_mode(regs)) - goto no_bug; /* Not in kernel */ - eip = regs->eip; if (eip < PAGE_OFFSET) |