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linux-user/x86_64: Allocate vsyscall page as a commpage

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We're about to start validating PAGE_EXEC, which means that we've
got to mark the vsyscall page executable.  We had been special
casing this entirely within translate.

Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2022-08-11 11:18:29 -07:00
parent eee816c0b9
commit d461b73ec0
1 changed files with 23 additions and 0 deletions
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23
linux-user/elfload.c
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@ -195,6 +195,27 @@ static void elf_core_copy_regs(target_elf_gregset_t *regs, const CPUX86State *en
(*regs)[26] = tswapreg(env->segs[R_GS].selector & 0xffff);
}
#if ULONG_MAX > UINT32_MAX
#define INIT_GUEST_COMMPAGE
static bool init_guest_commpage(void)
{
/*
* The vsyscall page is at a high negative address aka kernel space,
* which means that we cannot actually allocate it with target_mmap.
* We still should be able to use page_set_flags, unless the user
* has specified -R reserved_va, which would trigger an assert().
*/
if (reserved_va != 0 &&
TARGET_VSYSCALL_PAGE + TARGET_PAGE_SIZE >= reserved_va) {
error_report("Cannot allocate vsyscall page");
exit(EXIT_FAILURE);
}
page_set_flags(TARGET_VSYSCALL_PAGE,
TARGET_VSYSCALL_PAGE + TARGET_PAGE_SIZE,
PAGE_EXEC | PAGE_VALID);
return true;
}
#endif
#else
#define ELF_START_MMAP 0x80000000
@ -2360,8 +2381,10 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc,
#else
#define HI_COMMPAGE 0
#define LO_COMMPAGE -1
#ifndef INIT_GUEST_COMMPAGE
#define init_guest_commpage() true
#endif
#endif
static void pgb_fail_in_use(const char *image_name)
{