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linux-user: Explicitly untag memory management syscalls

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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>
Message-id: 20210212184902.1251044-14-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Richard Henderson 2021-02-12 10:48:44 -08:00 committed by Peter Maydell
parent 3e8f1628e8
commit ee1bf83de7
1 changed files with 11 additions and 0 deletions
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11
linux-user/syscall.c
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@ -894,6 +894,8 @@ 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) {
@ -4599,6 +4601,8 @@ 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)) {
@ -4666,6 +4670,8 @@ 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) {
@ -9703,6 +9709,7 @@ 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,
@ -9721,8 +9728,10 @@ 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. */
@ -9737,6 +9746,8 @@ 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. */