https://github.com/torvalds/linux
Revision bf85fa6c878aa3968df47d7f70a2b506c3e53b99 authored by Anton W\xf6llert on 27 July 2005, 07:45:17 UTC, committed by Linus Torvalds on 27 July 2005, 23:34:34 UTC
On 8xx, in the case where a pagefault happens for a process who's not the owner of the vma in question (ptrace for instance), the flush operation is performed via the physical address. Unfortunately, that results in a strange, unexplainable "icbi" instruction fault, most likely due to a CPU bug (see oops below). Avoid that by flushing the page via its kernel virtual address. Oops: kernel access of bad area, sig: 11 [#2] NIP: C000543C LR: C000B060 SP: C0F35DF0 REGS: c0f35d40 TRAP: 0300 Not tainted MSR: 00009022 EE: 1 PR: 0 FP: 0 ME: 1 IR/DR: 10 DAR: 00000010, DSISR: C2000000 TASK = c0ea8430[761] 'gdbserver' THREAD: c0f34000 Last syscall: 26 GPR00: 00009022 C0F35DF0 C0EA8430 00F59000 00000100 FFFFFFFF 00F58000 00000001 GPR08: C021DAEF C0270000 00009032 C0270000 22044024 10025428 01000800 00000001 GPR16: 007FFF3F 00000001 00000000 7FBC6AC0 00F61022 00000001 C0839300 C01E0000 GPR24: 00CD0889 C082F568 3000AC18 C02A7A00 C0EA15C8 00F588A9 C02ACB00 C02ACB00 NIP [c000543c] __flush_dcache_icache_phys+0x38/0x54 LR [c000b060] flush_dcache_icache_page+0x20/0x30 Call trace: [c000b154] update_mmu_cache+0x7c/0xa4 [c005ae98] do_wp_page+0x460/0x5ec [c005c8a0] handle_mm_fault+0x7cc/0x91c [c005ccec] get_user_pages+0x2fc/0x65c [c0027104] access_process_vm+0x9c/0x1d4 [c00076e0] sys_ptrace+0x240/0x4a4 [c0002bd0] ret_from_syscall+0x0/0x44 Signed-off-by: Marcelo Tosatti <marcelo.tosatti@cyclades.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
1 parent 5990415
Tip revision: bf85fa6c878aa3968df47d7f70a2b506c3e53b99 authored by Anton W\xf6llert on 27 July 2005, 07:45:17 UTC
[PATCH] ppc32: 8xx avoid icbi misbehaviour in __flush_dcache_icache_phys
[PATCH] ppc32: 8xx avoid icbi misbehaviour in __flush_dcache_icache_phys
Tip revision: bf85fa6
exec_domain.c
/*
* Handling of different ABIs (personalities).
*
* We group personalities into execution domains which have their
* own handlers for kernel entry points, signal mapping, etc...
*
* 2001-05-06 Complete rewrite, Christoph Hellwig (hch@infradead.org)
*/
#include <linux/config.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/kmod.h>
#include <linux/module.h>
#include <linux/personality.h>
#include <linux/sched.h>
#include <linux/syscalls.h>
#include <linux/sysctl.h>
#include <linux/types.h>
static void default_handler(int, struct pt_regs *);
static struct exec_domain *exec_domains = &default_exec_domain;
static DEFINE_RWLOCK(exec_domains_lock);
static u_long ident_map[32] = {
0, 1, 2, 3, 4, 5, 6, 7,
8, 9, 10, 11, 12, 13, 14, 15,
16, 17, 18, 19, 20, 21, 22, 23,
24, 25, 26, 27, 28, 29, 30, 31
};
struct exec_domain default_exec_domain = {
.name = "Linux", /* name */
.handler = default_handler, /* lcall7 causes a seg fault. */
.pers_low = 0, /* PER_LINUX personality. */
.pers_high = 0, /* PER_LINUX personality. */
.signal_map = ident_map, /* Identity map signals. */
.signal_invmap = ident_map, /* - both ways. */
};
static void
default_handler(int segment, struct pt_regs *regp)
{
set_personality(0);
if (current_thread_info()->exec_domain->handler != default_handler)
current_thread_info()->exec_domain->handler(segment, regp);
else
send_sig(SIGSEGV, current, 1);
}
static struct exec_domain *
lookup_exec_domain(u_long personality)
{
struct exec_domain * ep;
u_long pers = personality(personality);
read_lock(&exec_domains_lock);
for (ep = exec_domains; ep; ep = ep->next) {
if (pers >= ep->pers_low && pers <= ep->pers_high)
if (try_module_get(ep->module))
goto out;
}
#ifdef CONFIG_KMOD
read_unlock(&exec_domains_lock);
request_module("personality-%ld", pers);
read_lock(&exec_domains_lock);
for (ep = exec_domains; ep; ep = ep->next) {
if (pers >= ep->pers_low && pers <= ep->pers_high)
if (try_module_get(ep->module))
goto out;
}
#endif
ep = &default_exec_domain;
out:
read_unlock(&exec_domains_lock);
return (ep);
}
int
register_exec_domain(struct exec_domain *ep)
{
struct exec_domain *tmp;
int err = -EBUSY;
if (ep == NULL)
return -EINVAL;
if (ep->next != NULL)
return -EBUSY;
write_lock(&exec_domains_lock);
for (tmp = exec_domains; tmp; tmp = tmp->next) {
if (tmp == ep)
goto out;
}
ep->next = exec_domains;
exec_domains = ep;
err = 0;
out:
write_unlock(&exec_domains_lock);
return (err);
}
int
unregister_exec_domain(struct exec_domain *ep)
{
struct exec_domain **epp;
epp = &exec_domains;
write_lock(&exec_domains_lock);
for (epp = &exec_domains; *epp; epp = &(*epp)->next) {
if (ep == *epp)
goto unregister;
}
write_unlock(&exec_domains_lock);
return -EINVAL;
unregister:
*epp = ep->next;
ep->next = NULL;
write_unlock(&exec_domains_lock);
return 0;
}
int
__set_personality(u_long personality)
{
struct exec_domain *ep, *oep;
ep = lookup_exec_domain(personality);
if (ep == current_thread_info()->exec_domain) {
current->personality = personality;
return 0;
}
if (atomic_read(¤t->fs->count) != 1) {
struct fs_struct *fsp, *ofsp;
fsp = copy_fs_struct(current->fs);
if (fsp == NULL) {
module_put(ep->module);
return -ENOMEM;
}
task_lock(current);
ofsp = current->fs;
current->fs = fsp;
task_unlock(current);
put_fs_struct(ofsp);
}
/*
* At that point we are guaranteed to be the sole owner of
* current->fs.
*/
current->personality = personality;
oep = current_thread_info()->exec_domain;
current_thread_info()->exec_domain = ep;
set_fs_altroot();
module_put(oep->module);
return 0;
}
int
get_exec_domain_list(char *page)
{
struct exec_domain *ep;
int len = 0;
read_lock(&exec_domains_lock);
for (ep = exec_domains; ep && len < PAGE_SIZE - 80; ep = ep->next)
len += sprintf(page + len, "%d-%d\t%-16s\t[%s]\n",
ep->pers_low, ep->pers_high, ep->name,
module_name(ep->module));
read_unlock(&exec_domains_lock);
return (len);
}
asmlinkage long
sys_personality(u_long personality)
{
u_long old = current->personality;
if (personality != 0xffffffff) {
set_personality(personality);
if (current->personality != personality)
return -EINVAL;
}
return (long)old;
}
EXPORT_SYMBOL(register_exec_domain);
EXPORT_SYMBOL(unregister_exec_domain);
EXPORT_SYMBOL(__set_personality);
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