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tcg: Return the map protection from alloc_code_gen_buffer

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Change the interface from a boolean error indication to a
negative error vs a non-negative protection.  For the moment
this is only interface change, not making use of the new data.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2021-03-10 13:59:37 -06:00
parent 032a4b1ba0
commit 7be9ebcf92
1 changed files with 33 additions and 30 deletions
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63
tcg/region.c
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@ -526,14 +526,14 @@ static inline void split_cross_256mb(void **obuf, size_t *osize,
static uint8_t static_code_gen_buffer[DEFAULT_CODE_GEN_BUFFER_SIZE] static uint8_t static_code_gen_buffer[DEFAULT_CODE_GEN_BUFFER_SIZE]
__attribute__((aligned(CODE_GEN_ALIGN))); __attribute__((aligned(CODE_GEN_ALIGN)));
static bool alloc_code_gen_buffer(size_t tb_size, int splitwx, Error **errp) static int alloc_code_gen_buffer(size_t tb_size, int splitwx, Error **errp)
{ {
void *buf, *end; void *buf, *end;
size_t size; size_t size;
if (splitwx > 0) { if (splitwx > 0) {
error_setg(errp, "jit split-wx not supported"); error_setg(errp, "jit split-wx not supported");
return false; return -1;
} }
/* page-align the beginning and end of the buffer */ /* page-align the beginning and end of the buffer */
@ -563,16 +563,17 @@ static bool alloc_code_gen_buffer(size_t tb_size, int splitwx, Error **errp)
region.start_aligned = buf; region.start_aligned = buf;
region.total_size = size; region.total_size = size;
return true;
return PROT_READ | PROT_WRITE;
} }
#elif defined(_WIN32) #elif defined(_WIN32)
static bool alloc_code_gen_buffer(size_t size, int splitwx, Error **errp) static int alloc_code_gen_buffer(size_t size, int splitwx, Error **errp)
{ {
void *buf; void *buf;
if (splitwx > 0) { if (splitwx > 0) {
error_setg(errp, "jit split-wx not supported"); error_setg(errp, "jit split-wx not supported");
return false; return -1;
} }
buf = VirtualAlloc(NULL, size, MEM_RESERVE | MEM_COMMIT, buf = VirtualAlloc(NULL, size, MEM_RESERVE | MEM_COMMIT,
@ -585,11 +586,12 @@ static bool alloc_code_gen_buffer(size_t size, int splitwx, Error **errp)
region.start_aligned = buf; region.start_aligned = buf;
region.total_size = size; region.total_size = size;
return true;
return PAGE_READ | PAGE_WRITE | PAGE_EXEC;
} }
#else #else
static bool alloc_code_gen_buffer_anon(size_t size, int prot, static int alloc_code_gen_buffer_anon(size_t size, int prot,
int flags, Error **errp) int flags, Error **errp)
{ {
void *buf; void *buf;
@ -597,7 +599,7 @@ static bool alloc_code_gen_buffer_anon(size_t size, int prot,
if (buf == MAP_FAILED) { if (buf == MAP_FAILED) {
error_setg_errno(errp, errno, error_setg_errno(errp, errno,
"allocate %zu bytes for jit buffer", size); "allocate %zu bytes for jit buffer", size);
return false; return -1;
} }
#ifdef __mips__ #ifdef __mips__
@ -638,7 +640,7 @@ static bool alloc_code_gen_buffer_anon(size_t size, int prot,
region.start_aligned = buf; region.start_aligned = buf;
region.total_size = size; region.total_size = size;
return true; return prot;
} }
#ifndef CONFIG_TCG_INTERPRETER #ifndef CONFIG_TCG_INTERPRETER
@ -652,9 +654,9 @@ static bool alloc_code_gen_buffer_splitwx_memfd(size_t size, Error **errp)
#ifdef __mips__ #ifdef __mips__
/* Find space for the RX mapping, vs the 256MiB regions. */ /* Find space for the RX mapping, vs the 256MiB regions. */
if (!alloc_code_gen_buffer_anon(size, PROT_NONE, if (alloc_code_gen_buffer_anon(size, PROT_NONE,
MAP_PRIVATE | MAP_ANONYMOUS | MAP_PRIVATE | MAP_ANONYMOUS |
MAP_NORESERVE, errp)) { MAP_NORESERVE, errp) < 0) {
return false; return false;
} }
/* The size of the mapping may have been adjusted. */ /* The size of the mapping may have been adjusted. */
@ -688,7 +690,7 @@ static bool alloc_code_gen_buffer_splitwx_memfd(size_t size, Error **errp)
/* Request large pages for the buffer and the splitwx. */ /* Request large pages for the buffer and the splitwx. */
qemu_madvise(buf_rw, size, QEMU_MADV_HUGEPAGE); qemu_madvise(buf_rw, size, QEMU_MADV_HUGEPAGE);
qemu_madvise(buf_rx, size, QEMU_MADV_HUGEPAGE); qemu_madvise(buf_rx, size, QEMU_MADV_HUGEPAGE);
return true; return PROT_READ | PROT_WRITE;
fail_rx: fail_rx:
error_setg_errno(errp, errno, "failed to map shared memory for execute"); error_setg_errno(errp, errno, "failed to map shared memory for execute");
@ -702,7 +704,7 @@ static bool alloc_code_gen_buffer_splitwx_memfd(size_t size, Error **errp)
if (fd >= 0) { if (fd >= 0) {
close(fd); close(fd);
} }
return false; return -1;
} }
#endif /* CONFIG_POSIX */ #endif /* CONFIG_POSIX */
@ -721,7 +723,7 @@ extern kern_return_t mach_vm_remap(vm_map_t target_task,
vm_prot_t *max_protection, vm_prot_t *max_protection,
vm_inherit_t inheritance); vm_inherit_t inheritance);
static bool alloc_code_gen_buffer_splitwx_vmremap(size_t size, Error **errp) static int alloc_code_gen_buffer_splitwx_vmremap(size_t size, Error **errp)
{ {
kern_return_t ret; kern_return_t ret;
mach_vm_address_t buf_rw, buf_rx; mach_vm_address_t buf_rw, buf_rx;
@ -730,7 +732,7 @@ static bool alloc_code_gen_buffer_splitwx_vmremap(size_t size, Error **errp)
/* Map the read-write portion via normal anon memory. */ /* Map the read-write portion via normal anon memory. */
if (!alloc_code_gen_buffer_anon(size, PROT_READ | PROT_WRITE, if (!alloc_code_gen_buffer_anon(size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, errp)) { MAP_PRIVATE | MAP_ANONYMOUS, errp)) {
return false; return -1;
} }
buf_rw = (mach_vm_address_t)region.start_aligned; buf_rw = (mach_vm_address_t)region.start_aligned;
@ -750,23 +752,23 @@ static bool alloc_code_gen_buffer_splitwx_vmremap(size_t size, Error **errp)
/* TODO: Convert "ret" to a human readable error message. */ /* TODO: Convert "ret" to a human readable error message. */
error_setg(errp, "vm_remap for jit splitwx failed"); error_setg(errp, "vm_remap for jit splitwx failed");
munmap((void *)buf_rw, size); munmap((void *)buf_rw, size);
return false; return -1;
} }
if (mprotect((void *)buf_rx, size, PROT_READ | PROT_EXEC) != 0) { if (mprotect((void *)buf_rx, size, PROT_READ | PROT_EXEC) != 0) {
error_setg_errno(errp, errno, "mprotect for jit splitwx"); error_setg_errno(errp, errno, "mprotect for jit splitwx");
munmap((void *)buf_rx, size); munmap((void *)buf_rx, size);
munmap((void *)buf_rw, size); munmap((void *)buf_rw, size);
return false; return -1;
} }
tcg_splitwx_diff = buf_rx - buf_rw; tcg_splitwx_diff = buf_rx - buf_rw;
return true; return PROT_READ | PROT_WRITE;
} }
#endif /* CONFIG_DARWIN */ #endif /* CONFIG_DARWIN */
#endif /* CONFIG_TCG_INTERPRETER */ #endif /* CONFIG_TCG_INTERPRETER */
static bool alloc_code_gen_buffer_splitwx(size_t size, Error **errp) static int alloc_code_gen_buffer_splitwx(size_t size, Error **errp)
{ {
#ifndef CONFIG_TCG_INTERPRETER #ifndef CONFIG_TCG_INTERPRETER
# ifdef CONFIG_DARWIN # ifdef CONFIG_DARWIN
@ -777,24 +779,25 @@ static bool alloc_code_gen_buffer_splitwx(size_t size, Error **errp)
# endif # endif
#endif #endif
error_setg(errp, "jit split-wx not supported"); error_setg(errp, "jit split-wx not supported");
return false; return -1;
} }
static bool alloc_code_gen_buffer(size_t size, int splitwx, Error **errp) static int alloc_code_gen_buffer(size_t size, int splitwx, Error **errp)
{ {
ERRP_GUARD(); ERRP_GUARD();
int prot, flags; int prot, flags;
if (splitwx) { if (splitwx) {
if (alloc_code_gen_buffer_splitwx(size, errp)) { prot = alloc_code_gen_buffer_splitwx(size, errp);
return true; if (prot >= 0) {
return prot;
} }
/* /*
* If splitwx force-on (1), fail; * If splitwx force-on (1), fail;
* if splitwx default-on (-1), fall through to splitwx off. * if splitwx default-on (-1), fall through to splitwx off.
*/ */
if (splitwx > 0) { if (splitwx > 0) {
return false; return -1;
} }
error_free_or_abort(errp); error_free_or_abort(errp);
} }
@ -848,11 +851,11 @@ void tcg_region_init(size_t tb_size, int splitwx, unsigned max_cpus)
size_t page_size; size_t page_size;
size_t region_size; size_t region_size;
size_t i; size_t i;
bool ok; int have_prot;
ok = alloc_code_gen_buffer(size_code_gen_buffer(tb_size), have_prot = alloc_code_gen_buffer(size_code_gen_buffer(tb_size),
splitwx, &error_fatal); splitwx, &error_fatal);
assert(ok); assert(have_prot >= 0);
/* /*
* Make region_size a multiple of page_size, using aligned as the start. * Make region_size a multiple of page_size, using aligned as the start.