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translate-all.c: Don't pass puc, locked to tb_invalidate_phys_page()

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The user-mode-only function tb_invalidate_phys_page() is only
called from two places:
* page_unprotect(), which passes in a non-zero pc, a puc pointer
and the value 'true' for the locked argument
* page_set_flags(), which passes in a zero pc, a NULL puc pointer
and a 'false' locked argument

If the pc is non-zero then we may call cpu_resume_from_signal(),
which does a longjmp out of the calling code (and out of the
signal handler); this is to cover the case of a target CPU with
"precise self-modifying code" (currently only x86) executing
a store instruction which modifies code in the same TB as the
store itself. Rather than doing the longjump directly here,
return a flag to the caller which indicates whether the current
TB was modified, and move the longjump to page_unprotect.

Backports commit 75809229bbf28b371afce14921ff5be98ddc5faa from qemu
This commit is contained in:
Peter Maydell 2018-02-24 17:11:25 -05:00 committed by Lioncash
parent 1db22b5889
commit 37b7538d85
No known key found for this signature in database
GPG key ID: 4E3C3CC1031BA9C7
1 changed files with 15 additions and 10 deletions
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25
qemu/translate-all.c
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@ -1548,9 +1548,13 @@ void tb_invalidate_phys_page_fast(struct uc_struct* uc, tb_page_addr_t start, in
}
}
#else
static void tb_invalidate_phys_page(struct uc_struct *uc, tb_page_addr_t addr,
uintptr_t pc, void *puc,
bool locked)
/* Called with mmap_lock held. If pc is not 0 then it indicates the
* host PC of the faulting store instruction that caused this invalidate.
* Returns true if the caller needs to abort execution of the current
* TB (because it was modified by this store and the guest CPU has
* precise-SMC semantics).
*/
static bool tb_invalidate_phys_page(tb_page_addr_t addr, uintptr_t pc)
{
TranslationBlock *tb;
PageDesc *p;
@ -1568,7 +1572,7 @@ static void tb_invalidate_phys_page(struct uc_struct *uc, tb_page_addr_t addr,
addr &= TARGET_PAGE_MASK;
p = page_find(addr >> TARGET_PAGE_BITS);
if (!p) {
return;
return false;
}
tb = p->first_tb;
#ifdef TARGET_HAS_PRECISE_SMC
@ -1607,12 +1611,10 @@ static void tb_invalidate_phys_page(struct uc_struct *uc, tb_page_addr_t addr,
modifying the memory. It will ensure that it cannot modify
itself */
tb_gen_code(cpu, current_pc, current_cs_base, current_flags, 1);
if (locked) {
mmap_unlock();
}
cpu_resume_from_signal(cpu, puc);
return true;
}
#endif
return false;
}
#endif
@ -2005,7 +2007,7 @@ static void page_set_flags(struct uc_struct *uc, target_ulong start, target_ulon
if (!(p->flags & PAGE_WRITE) &&
(flags & PAGE_WRITE) &&
p->first_tb) {
tb_invalidate_phys_page(addr, 0, NULL, false);
tb_invalidate_phys_page(addr, 0);
}
p->flags = flags;
}
@ -2099,7 +2101,10 @@ static int page_unprotect(target_ulong address, uintptr_t pc, void *puc)
/* and since the content will be modified, we must invalidate
the corresponding translated code. */
tb_invalidate_phys_page(addr, pc, puc, true);
if (tb_invalidate_phys_page(addr, pc)) {
mmap_unlock();
cpu_resume_from_signal(current_cpu, puc);
}
#ifdef DEBUG_TB_CHECK
tb_invalidate_check(addr);
#endif