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[PATCH for-7.2 03/21] linux-user/x86_64: Allocate vsyscall page as a com
From: |
Richard Henderson |
Subject: |
[PATCH for-7.2 03/21] linux-user/x86_64: Allocate vsyscall page as a commpage |
Date: |
Fri, 12 Aug 2022 11:07:48 -0700 |
We're about to start validating PAGE_EXEC, which means that we've
got to the vsyscall page executable. We had been special casing
this entirely within translate.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
linux-user/elfload.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 29d910c4cc..e315155dad 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -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);
}
+#define HI_COMMPAGE TARGET_VSYSCALL_PAGE
+
+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;
+}
+
#else
#define ELF_START_MMAP 0x80000000
--
2.34.1
- [PATCH for-7.2 00/21] accel/tcg: minimize tlb lookups during translate + user-only PROT_EXEC fixes, Richard Henderson, 2022/08/12
- [PATCH for-7.2 01/21] linux-user/arm: Mark the commpage executable, Richard Henderson, 2022/08/12
- [PATCH for-7.2 02/21] linux-user/hppa: Allocate page zero as a commpage, Richard Henderson, 2022/08/12
- [PATCH for-7.2 04/21] linux-user: Honor PT_GNU_STACK, Richard Henderson, 2022/08/12
- [PATCH for-7.2 05/21] tests/tcg/i386: Move smc_code2 to an executable section, Richard Henderson, 2022/08/12
- [PATCH for-7.2 08/21] accel/tcg: Merge tb_htable_lookup into caller, Richard Henderson, 2022/08/12
- [PATCH for-7.2 07/21] accel/tcg: Use bool for page_find_alloc, Richard Henderson, 2022/08/12
- [PATCH for-7.2 10/21] accel/tcg: Properly implement get_page_addr_code for user-only, Richard Henderson, 2022/08/12
- [PATCH for-7.2 11/21] accel/tcg: Use probe_access_internal for softmmu get_page_addr_code_hostp, Richard Henderson, 2022/08/12
- [PATCH for-7.2 03/21] linux-user/x86_64: Allocate vsyscall page as a commpage,
Richard Henderson <=
- [PATCH for-7.2 06/21] accel/tcg: Remove PageDesc code_bitmap, Richard Henderson, 2022/08/12
- [PATCH for-7.2 09/21] accel/tcg: Move qemu_ram_addr_from_host_nofail to physmem.c, Richard Henderson, 2022/08/12
- [PATCH for-7.2 13/21] accel/tcg: Unlock mmap_lock after longjmp, Richard Henderson, 2022/08/12
- [PATCH for-7.2 14/21] accel/tcg: Hoist get_page_addr_code out of tb_lookup, Richard Henderson, 2022/08/12
- Re: [PATCH for-7.2 14/21] accel/tcg: Hoist get_page_addr_code out of tb_lookup, Ilya Leoshkevich, 2022/08/16
- Re: [PATCH for-7.2 14/21] accel/tcg: Hoist get_page_addr_code out of tb_lookup, Richard Henderson, 2022/08/16
- Re: [PATCH for-7.2 14/21] accel/tcg: Hoist get_page_addr_code out of tb_lookup, Ilya Leoshkevich, 2022/08/17
- Re: [PATCH for-7.2 14/21] accel/tcg: Hoist get_page_addr_code out of tb_lookup, Richard Henderson, 2022/08/17
- Re: [PATCH for-7.2 14/21] accel/tcg: Hoist get_page_addr_code out of tb_lookup, Ilya Leoshkevich, 2022/08/17
- Re: [PATCH for-7.2 14/21] accel/tcg: Hoist get_page_addr_code out of tb_lookup, Richard Henderson, 2022/08/17