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tcg: Map code_gen_buffer with PROT_BTI

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For linux aarch64 host supporting BTI, map the buffer
to require BTI instructions at branch landing pads.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2023-08-15 17:53:42 -07:00
parent 5826a0dbf0
commit a97a83753c
1 changed files with 30 additions and 11 deletions
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41
tcg/region.c
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@ -33,8 +33,19 @@
#include "tcg/tcg.h"
#include "exec/translation-block.h"
#include "tcg-internal.h"
#include "host/cpuinfo.h"
/*
* Local source-level compatibility with Unix.
* Used by tcg_region_init below.
*/
#if defined(_WIN32)
#define PROT_READ 1
#define PROT_WRITE 2
#define PROT_EXEC 4
#endif
struct tcg_region_tree {
QemuMutex lock;
QTree *tree;
@ -83,6 +94,18 @@ bool in_code_gen_buffer(const void *p)
return (size_t)(p - region.start_aligned) <= region.total_size;
}
#ifndef CONFIG_TCG_INTERPRETER
static int host_prot_read_exec(void)
{
#if defined(CONFIG_LINUX) && defined(HOST_AARCH64) && defined(PROT_BTI)
if (cpuinfo & CPUINFO_BTI) {
return PROT_READ | PROT_EXEC | PROT_BTI;
}
#endif
return PROT_READ | PROT_EXEC;
}
#endif
#ifdef CONFIG_DEBUG_TCG
const void *tcg_splitwx_to_rx(void *rw)
{
@ -505,14 +528,6 @@ static int alloc_code_gen_buffer(size_t tb_size, int splitwx, Error **errp)
return PROT_READ | PROT_WRITE;
}
#elif defined(_WIN32)
/*
* Local source-level compatibility with Unix.
* Used by tcg_region_init below.
*/
#define PROT_READ 1
#define PROT_WRITE 2
#define PROT_EXEC 4
static int alloc_code_gen_buffer(size_t size, int splitwx, Error **errp)
{
void *buf;
@ -567,7 +582,7 @@ static int alloc_code_gen_buffer_splitwx_memfd(size_t size, Error **errp)
goto fail;
}
buf_rx = mmap(NULL, size, PROT_READ | PROT_EXEC, MAP_SHARED, fd, 0);
buf_rx = mmap(NULL, size, host_prot_read_exec(), MAP_SHARED, fd, 0);
if (buf_rx == MAP_FAILED) {
goto fail_rx;
}
@ -642,7 +657,7 @@ static int alloc_code_gen_buffer_splitwx_vmremap(size_t size, Error **errp)
return -1;
}
if (mprotect((void *)buf_rx, size, PROT_READ | PROT_EXEC) != 0) {
if (mprotect((void *)buf_rx, size, host_prot_read_exec()) != 0) {
error_setg_errno(errp, errno, "mprotect for jit splitwx");
munmap((void *)buf_rx, size);
munmap((void *)buf_rw, size);
@ -805,7 +820,7 @@ void tcg_region_init(size_t tb_size, int splitwx, unsigned max_cpus)
need_prot = PROT_READ | PROT_WRITE;
#ifndef CONFIG_TCG_INTERPRETER
if (tcg_splitwx_diff == 0) {
need_prot |= PROT_EXEC;
need_prot |= host_prot_read_exec();
}
#endif
for (size_t i = 0, n = region.n; i < n; i++) {
@ -820,7 +835,11 @@ void tcg_region_init(size_t tb_size, int splitwx, unsigned max_cpus)
} else if (need_prot == (PROT_READ | PROT_WRITE)) {
rc = qemu_mprotect_rw(start, end - start);
} else {
#ifdef CONFIG_POSIX
rc = mprotect(start, end - start, need_prot);
#else
g_assert_not_reached();
#endif
}
if (rc) {
error_setg_errno(&error_fatal, errno,