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[PATCH v7 13/31] linux-user: Explicitly untag memory management syscalls
From: |
Richard Henderson |
Subject: |
[PATCH v7 13/31] linux-user: Explicitly untag memory management syscalls |
Date: |
Fri, 12 Feb 2021 10:48:44 -0800 |
We define target_mmap et al as untagged, so that they can be
used from the binary loaders. Explicitly call cpu_untagged_addr
for munmap, mprotect, mremap syscall entry points.
Add a few comments for the syscalls that are exempted by the
kernel's tagged-address-abi.rst.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
linux-user/syscall.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 748893904e..4451f8e4f0 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -889,6 +889,8 @@ abi_long do_brk(abi_ulong new_brk)
abi_long mapped_addr;
abi_ulong new_alloc_size;
+ /* brk pointers are always untagged */
+
DEBUGF_BRK("do_brk(" TARGET_ABI_FMT_lx ") -> ", new_brk);
if (!new_brk) {
@@ -4588,6 +4590,8 @@ static inline abi_ulong do_shmat(CPUArchState *cpu_env,
int i,ret;
abi_ulong shmlba;
+ /* shmat pointers are always untagged */
+
/* find out the length of the shared memory segment */
ret = get_errno(shmctl(shmid, IPC_STAT, &shm_info));
if (is_error(ret)) {
@@ -4655,6 +4659,8 @@ static inline abi_long do_shmdt(abi_ulong shmaddr)
int i;
abi_long rv;
+ /* shmdt pointers are always untagged */
+
mmap_lock();
for (i = 0; i < N_SHM_REGIONS; ++i) {
@@ -9691,6 +9697,7 @@ static abi_long do_syscall1(void *cpu_env, int num,
abi_long arg1,
v5, v6));
}
#else
+ /* mmap pointers are always untagged */
ret = get_errno(target_mmap(arg1, arg2, arg3,
target_to_host_bitmask(arg4,
mmap_flags_tbl),
arg5,
@@ -9709,8 +9716,10 @@ static abi_long do_syscall1(void *cpu_env, int num,
abi_long arg1,
return get_errno(ret);
#endif
case TARGET_NR_munmap:
+ arg1 = cpu_untagged_addr(cpu, arg1);
return get_errno(target_munmap(arg1, arg2));
case TARGET_NR_mprotect:
+ arg1 = cpu_untagged_addr(cpu, arg1);
{
TaskState *ts = cpu->opaque;
/* Special hack to detect libc making the stack executable. */
@@ -9725,6 +9734,8 @@ static abi_long do_syscall1(void *cpu_env, int num,
abi_long arg1,
return get_errno(target_mprotect(arg1, arg2, arg3));
#ifdef TARGET_NR_mremap
case TARGET_NR_mremap:
+ arg1 = cpu_untagged_addr(cpu, arg1);
+ /* mremap new_addr (arg5) is always untagged */
return get_errno(target_mremap(arg1, arg2, arg3, arg4, arg5));
#endif
/* ??? msync/mlock/munlock are broken for softmmu. */
--
2.25.1
- [PATCH v7 00/31] target-arm: Implement ARMv8.5-MemTag, user mode, Richard Henderson, 2021/02/12
- [PATCH v7 01/31] tcg: Introduce target-specific page data for user-only, Richard Henderson, 2021/02/12
- [PATCH v7 02/31] linux-user: Introduce PAGE_ANON, Richard Henderson, 2021/02/12
- [PATCH v7 03/31] exec: Use uintptr_t for guest_base, Richard Henderson, 2021/02/12
- [PATCH v7 05/31] exec: Improve types for guest_addr_valid, Richard Henderson, 2021/02/12
- [PATCH v7 04/31] exec: Use uintptr_t in cpu_ldst.h, Richard Henderson, 2021/02/12
- [PATCH v7 08/31] bsd-user: Tidy VERIFY_READ/VERIFY_WRITE, Richard Henderson, 2021/02/12
- [PATCH v7 13/31] linux-user: Explicitly untag memory management syscalls,
Richard Henderson <=
- [PATCH v7 09/31] linux-user: Do not use guest_addr_valid for h2g_valid, Richard Henderson, 2021/02/12
- [PATCH v7 07/31] linux-user: Tidy VERIFY_READ/VERIFY_WRITE, Richard Henderson, 2021/02/12
- [PATCH v7 12/31] exec: Use cpu_untagged_addr in g2h; split out g2h_untagged, Richard Henderson, 2021/02/12
- [PATCH v7 15/31] exec: Rename guest_{addr,range}_valid to *_untagged, Richard Henderson, 2021/02/12
- [PATCH v7 11/31] exec: Introduce cpu_untagged_addr, Richard Henderson, 2021/02/12
- [PATCH v7 10/31] linux-user: Fix guest_addr_valid vs reserved_va, Richard Henderson, 2021/02/12
- [PATCH v7 22/31] target/arm: Use the proper TBI settings for linux-user, Richard Henderson, 2021/02/12
- [PATCH v7 19/31] linux-user: Handle tags in lock_user/unlock_user, Richard Henderson, 2021/02/12
- [PATCH v7 06/31] linux-user: Check for overflow in access_ok, Richard Henderson, 2021/02/12
- [PATCH v7 16/31] linux-user: Use cpu_untagged_addr in access_ok; split out *_untagged, Richard Henderson, 2021/02/12