public inbox for gcc-cvs@sourceware.org
help / color / mirror / Atom feed
* [gcc r14-4823] libgcc: support heap-based trampolines
@ 2023-10-22 13:01 Iain D Sandoe
0 siblings, 0 replies; only message in thread
From: Iain D Sandoe @ 2023-10-22 13:01 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:8abddb187b33480d8827f44ec655f45734a1749d
commit r14-4823-g8abddb187b33480d8827f44ec655f45734a1749d
Author: Andrew Burgess <andrew.burgess@embecosm.com>
Date: Sat Aug 5 14:31:06 2023 +0200
libgcc: support heap-based trampolines
Add support for heap-based trampolines on x86_64-linux, aarch64-linux,
and x86_64-darwin. Implement the __builtin_nested_func_ptr_created and
__builtin_nested_func_ptr_deleted functions for these targets.
Co-Authored-By: Maxim Blinov <maxim.blinov@embecosm.com>
Co-Authored-By: Iain Sandoe <iain@sandoe.co.uk>
Co-Authored-By: Francois-Xavier Coudert <fxcoudert@gcc.gnu.org>
libgcc/ChangeLog:
* libgcc2.h (__builtin_nested_func_ptr_created): Declare.
(__builtin_nested_func_ptr_deleted): Declare.
* libgcc-std.ver.in: Add the new symbols.
* config/aarch64/heap-trampoline.c: Implement heap-based
trampolines for aarch64.
* config/aarch64/t-heap-trampoline: Add rule to build
config/aarch64/heap-trampoline.c
* config/i386/heap-trampoline.c: Implement heap-based
trampolines for x86_64.
* config/i386/t-heap-trampoline: Add rule to build
config/i386/heap-trampoline.cc
* config.host: Handle --enable-heap-trampolines on
x86_64-*-linux*, aarch64-*-linux*, x86_64-*-darwin*.
Diff:
---
libgcc/config.host | 3 +
libgcc/config/aarch64/heap-trampoline.c | 172 ++++++++++++++++++++++++++++++++
libgcc/config/aarch64/t-heap-trampoline | 19 ++++
libgcc/config/i386/heap-trampoline.c | 172 ++++++++++++++++++++++++++++++++
libgcc/config/i386/t-heap-trampoline | 19 ++++
libgcc/libgcc-std.ver.in | 3 +
libgcc/libgcc2.h | 3 +
7 files changed, 391 insertions(+)
diff --git a/libgcc/config.host b/libgcc/config.host
index 6a112a07b140..a676b2f89802 100644
--- a/libgcc/config.host
+++ b/libgcc/config.host
@@ -423,6 +423,7 @@ aarch64*-*-linux*)
tmake_file="${tmake_file} ${cpu_type}/t-lse t-slibgcc-libgcc"
tmake_file="${tmake_file} ${cpu_type}/t-softfp t-softfp t-crtfm"
tmake_file="${tmake_file} t-dfprules"
+ tmake_file="${tmake_file} ${cpu_type}/t-heap-trampoline"
;;
aarch64*-*-vxworks7*)
extra_parts="$extra_parts crtfastmath.o"
@@ -697,6 +698,7 @@ x86_64-*-darwin*)
tmake_file="$tmake_file i386/t-crtpc t-crtfm i386/t-msabi"
tm_file="$tm_file i386/darwin-lib.h"
extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o crtfastmath.o"
+ tmake_file="${tmake_file} i386/t-heap-trampoline"
;;
i[34567]86-*-elfiamcu)
tmake_file="$tmake_file i386/t-crtstuff t-softfp-sfdftf i386/32/t-softfp i386/32/t-iamcu i386/t-softfp t-softfp t-dfprules"
@@ -763,6 +765,7 @@ x86_64-*-linux*)
tmake_file="${tmake_file} i386/t-crtpc t-crtfm i386/t-crtstuff t-dfprules"
tm_file="${tm_file} i386/elf-lib.h"
md_unwind_header=i386/linux-unwind.h
+ tmake_file="${tmake_file} i386/t-heap-trampoline"
;;
x86_64-*-kfreebsd*-gnu)
extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o crtfastmath.o"
diff --git a/libgcc/config/aarch64/heap-trampoline.c b/libgcc/config/aarch64/heap-trampoline.c
new file mode 100644
index 000000000000..c8b83681ed7e
--- /dev/null
+++ b/libgcc/config/aarch64/heap-trampoline.c
@@ -0,0 +1,172 @@
+/* Copyright The GNU Toolchain Authors. */
+
+#include <unistd.h>
+#include <sys/mman.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#if __APPLE__
+/* For pthread_jit_write_protect_np */
+#include <pthread.h>
+#endif
+
+void *allocate_trampoline_page (void);
+int get_trampolines_per_page (void);
+struct tramp_ctrl_data *allocate_tramp_ctrl (struct tramp_ctrl_data *parent);
+void *allocate_trampoline_page (void);
+
+void __builtin_nested_func_ptr_created (void *chain, void *func, void **dst);
+void __builtin_nested_func_ptr_deleted (void);
+
+#if defined(__gnu_linux__)
+static const uint32_t aarch64_trampoline_insns[] = {
+ 0xd503245f, /* hint 34 */
+ 0x580000b1, /* ldr x17, .+20 */
+ 0x580000d2, /* ldr x18, .+24 */
+ 0xd61f0220, /* br x17 */
+ 0xd5033f9f, /* dsb sy */
+ 0xd5033fdf /* isb */
+};
+
+#elif __APPLE__
+static const uint32_t aarch64_trampoline_insns[] = {
+ 0xd503245f, /* hint 34 */
+ 0x580000b1, /* ldr x17, .+20 */
+ 0x580000d0, /* ldr x16, .+24 */
+ 0xd61f0220, /* br x17 */
+ 0xd5033f9f, /* dsb sy */
+ 0xd5033fdf /* isb */
+};
+
+#else
+#error "Unsupported AArch64 platform for heap trampolines"
+#endif
+
+struct aarch64_trampoline {
+ uint32_t insns[6];
+ void *func_ptr;
+ void *chain_ptr;
+};
+
+struct tramp_ctrl_data
+{
+ struct tramp_ctrl_data *prev;
+
+ int free_trampolines;
+
+ /* This will be pointing to an executable mmap'ed page. */
+ struct aarch64_trampoline *trampolines;
+};
+
+int
+get_trampolines_per_page (void)
+{
+ return getpagesize() / sizeof(struct aarch64_trampoline);
+}
+
+static _Thread_local struct tramp_ctrl_data *tramp_ctrl_curr = NULL;
+
+void *
+allocate_trampoline_page (void)
+{
+ void *page;
+
+#if defined(__gnu_linux__)
+ page = mmap (0, getpagesize (), PROT_WRITE | PROT_EXEC,
+ MAP_ANON | MAP_PRIVATE, 0, 0);
+#elif __APPLE__
+ page = mmap (0, getpagesize (), PROT_WRITE | PROT_EXEC,
+ MAP_ANON | MAP_PRIVATE | MAP_JIT, 0, 0);
+#else
+ page = MAP_FAILED;
+#endif
+
+ return page;
+}
+
+struct tramp_ctrl_data *
+allocate_tramp_ctrl (struct tramp_ctrl_data *parent)
+{
+ struct tramp_ctrl_data *p = malloc (sizeof (struct tramp_ctrl_data));
+ if (p == NULL)
+ return NULL;
+
+ p->trampolines = allocate_trampoline_page ();
+
+ if (p->trampolines == MAP_FAILED)
+ return NULL;
+
+ p->prev = parent;
+ p->free_trampolines = get_trampolines_per_page();
+
+ return p;
+}
+
+void
+__builtin_nested_func_ptr_created (void *chain, void *func, void **dst)
+{
+ if (tramp_ctrl_curr == NULL)
+ {
+ tramp_ctrl_curr = allocate_tramp_ctrl (NULL);
+ if (tramp_ctrl_curr == NULL)
+ abort ();
+ }
+
+ if (tramp_ctrl_curr->free_trampolines == 0)
+ {
+ void *tramp_ctrl = allocate_tramp_ctrl (tramp_ctrl_curr);
+ if (!tramp_ctrl)
+ abort ();
+
+ tramp_ctrl_curr = tramp_ctrl;
+ }
+
+ struct aarch64_trampoline *trampoline
+ = &tramp_ctrl_curr->trampolines[get_trampolines_per_page ()
+ - tramp_ctrl_curr->free_trampolines];
+
+#if __APPLE__
+ /* Disable write protection for the MAP_JIT regions in this thread (see
+ https://developer.apple.com/documentation/apple-silicon/porting-just-in-time-compilers-to-apple-silicon) */
+ pthread_jit_write_protect_np (0);
+#endif
+
+ memcpy (trampoline->insns, aarch64_trampoline_insns,
+ sizeof(aarch64_trampoline_insns));
+ trampoline->func_ptr = func;
+ trampoline->chain_ptr = chain;
+
+#if __APPLE__
+ /* Re-enable write protection. */
+ pthread_jit_write_protect_np (1);
+#endif
+
+ tramp_ctrl_curr->free_trampolines -= 1;
+
+ __builtin___clear_cache ((void *)trampoline->insns,
+ ((void *)trampoline->insns + sizeof(trampoline->insns)));
+
+ *dst = &trampoline->insns;
+}
+
+void
+__builtin_nested_func_ptr_deleted (void)
+{
+ if (tramp_ctrl_curr == NULL)
+ abort ();
+
+ tramp_ctrl_curr->free_trampolines += 1;
+
+ if (tramp_ctrl_curr->free_trampolines == get_trampolines_per_page ())
+ {
+ if (tramp_ctrl_curr->prev == NULL)
+ return;
+
+ munmap (tramp_ctrl_curr->trampolines, getpagesize());
+ struct tramp_ctrl_data *prev = tramp_ctrl_curr->prev;
+ free (tramp_ctrl_curr);
+ tramp_ctrl_curr = prev;
+ }
+}
diff --git a/libgcc/config/aarch64/t-heap-trampoline b/libgcc/config/aarch64/t-heap-trampoline
new file mode 100644
index 000000000000..b22480800b22
--- /dev/null
+++ b/libgcc/config/aarch64/t-heap-trampoline
@@ -0,0 +1,19 @@
+# Copyright The GNU Toolchain Authors.
+
+# This file is part of GCC.
+#
+# GCC is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+#
+# GCC is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with GCC; see the file COPYING3. If not see
+# <http://www.gnu.org/licenses/>.
+
+LIB2ADD += $(srcdir)/config/aarch64/heap-trampoline.c
diff --git a/libgcc/config/i386/heap-trampoline.c b/libgcc/config/i386/heap-trampoline.c
new file mode 100644
index 000000000000..96e13bf828ea
--- /dev/null
+++ b/libgcc/config/i386/heap-trampoline.c
@@ -0,0 +1,172 @@
+/* Copyright The GNU Toolchain Authors. */
+
+#include <unistd.h>
+#include <sys/mman.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#if __APPLE__ && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 101400
+/* For pthread_jit_write_protect_np */
+#include <pthread.h>
+#endif
+
+void *allocate_trampoline_page (void);
+int get_trampolines_per_page (void);
+struct tramp_ctrl_data *allocate_tramp_ctrl (struct tramp_ctrl_data *parent);
+void *allocate_trampoline_page (void);
+
+void __builtin_nested_func_ptr_created (void *chain, void *func, void **dst);
+void __builtin_nested_func_ptr_deleted (void);
+
+static const uint8_t trampoline_insns[] = {
+ /* movabs $<chain>,%r11 */
+ 0x49, 0xbb,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+
+ /* movabs $<func>,%r10 */
+ 0x49, 0xba,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+
+ /* rex.WB jmpq *%r11 */
+ 0x41, 0xff, 0xe3
+};
+
+union ix86_trampoline {
+ uint8_t insns[sizeof(trampoline_insns)];
+
+ struct __attribute__((packed)) fields {
+ uint8_t insn_0[2];
+ void *func_ptr;
+ uint8_t insn_1[2];
+ void *chain_ptr;
+ uint8_t insn_2[3];
+ } fields;
+};
+
+struct tramp_ctrl_data
+{
+ struct tramp_ctrl_data *prev;
+
+ int free_trampolines;
+
+ /* This will be pointing to an executable mmap'ed page. */
+ union ix86_trampoline *trampolines;
+};
+
+int
+get_trampolines_per_page (void)
+{
+ return getpagesize() / sizeof(union ix86_trampoline);
+}
+
+static _Thread_local struct tramp_ctrl_data *tramp_ctrl_curr = NULL;
+
+void *
+allocate_trampoline_page (void)
+{
+ void *page;
+
+#if defined(__gnu_linux__)
+ page = mmap (0, getpagesize (), PROT_WRITE | PROT_EXEC,
+ MAP_ANON | MAP_PRIVATE, 0, 0);
+#elif __APPLE__
+# if __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 101400
+ page = mmap (0, getpagesize (), PROT_WRITE | PROT_EXEC,
+ MAP_ANON | MAP_PRIVATE | MAP_JIT, 0, 0);
+# else
+ page = mmap (0, getpagesize (), PROT_WRITE | PROT_EXEC,
+ MAP_ANON | MAP_PRIVATE, 0, 0);
+# endif
+#else
+ page = MAP_FAILED;
+#endif
+
+ return page;
+}
+
+struct tramp_ctrl_data *
+allocate_tramp_ctrl (struct tramp_ctrl_data *parent)
+{
+ struct tramp_ctrl_data *p = malloc (sizeof (struct tramp_ctrl_data));
+ if (p == NULL)
+ return NULL;
+
+ p->trampolines = allocate_trampoline_page ();
+
+ if (p->trampolines == MAP_FAILED)
+ return NULL;
+
+ p->prev = parent;
+ p->free_trampolines = get_trampolines_per_page();
+
+ return p;
+}
+
+void
+__builtin_nested_func_ptr_created (void *chain, void *func, void **dst)
+{
+ if (tramp_ctrl_curr == NULL)
+ {
+ tramp_ctrl_curr = allocate_tramp_ctrl (NULL);
+ if (tramp_ctrl_curr == NULL)
+ abort ();
+ }
+
+ if (tramp_ctrl_curr->free_trampolines == 0)
+ {
+ void *tramp_ctrl = allocate_tramp_ctrl (tramp_ctrl_curr);
+ if (!tramp_ctrl)
+ abort ();
+
+ tramp_ctrl_curr = tramp_ctrl;
+ }
+
+ union ix86_trampoline *trampoline
+ = &tramp_ctrl_curr->trampolines[get_trampolines_per_page ()
+ - tramp_ctrl_curr->free_trampolines];
+
+#if __APPLE__ && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 101400
+ /* Disable write protection for the MAP_JIT regions in this thread (see
+ https://developer.apple.com/documentation/apple-silicon/porting-just-in-time-compilers-to-apple-silicon) */
+ pthread_jit_write_protect_np (0);
+#endif
+
+ memcpy (trampoline->insns, trampoline_insns,
+ sizeof(trampoline_insns));
+ trampoline->fields.func_ptr = func;
+ trampoline->fields.chain_ptr = chain;
+
+#if __APPLE__ && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 101400
+ /* Re-enable write protection. */
+ pthread_jit_write_protect_np (1);
+#endif
+
+ tramp_ctrl_curr->free_trampolines -= 1;
+
+ __builtin___clear_cache ((void *)trampoline->insns,
+ ((void *)trampoline->insns + sizeof(trampoline->insns)));
+
+ *dst = &trampoline->insns;
+}
+
+void
+__builtin_nested_func_ptr_deleted (void)
+{
+ if (tramp_ctrl_curr == NULL)
+ abort ();
+
+ tramp_ctrl_curr->free_trampolines += 1;
+
+ if (tramp_ctrl_curr->free_trampolines == get_trampolines_per_page ())
+ {
+ if (tramp_ctrl_curr->prev == NULL)
+ return;
+
+ munmap (tramp_ctrl_curr->trampolines, getpagesize());
+ struct tramp_ctrl_data *prev = tramp_ctrl_curr->prev;
+ free (tramp_ctrl_curr);
+ tramp_ctrl_curr = prev;
+ }
+}
diff --git a/libgcc/config/i386/t-heap-trampoline b/libgcc/config/i386/t-heap-trampoline
new file mode 100644
index 000000000000..613f635b1f63
--- /dev/null
+++ b/libgcc/config/i386/t-heap-trampoline
@@ -0,0 +1,19 @@
+# Copyright The GNU Toolchain Authors.
+
+# This file is part of GCC.
+#
+# GCC is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+#
+# GCC is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with GCC; see the file COPYING3. If not see
+# <http://www.gnu.org/licenses/>.
+
+LIB2ADD += $(srcdir)/config/i386/heap-trampoline.c
diff --git a/libgcc/libgcc-std.ver.in b/libgcc/libgcc-std.ver.in
index 34d61c68d7e5..f092752136af 100644
--- a/libgcc/libgcc-std.ver.in
+++ b/libgcc/libgcc-std.ver.in
@@ -1943,6 +1943,9 @@ GCC_4.8.0 {
GCC_7.0.0 {
__PFX__divmoddi4
__PFX__divmodti4
+
+ __builtin_nested_func_ptr_created
+ __builtin_nested_func_ptr_deleted
}
%inherit GCC_14.0.0 GCC_7.0.0
diff --git a/libgcc/libgcc2.h b/libgcc/libgcc2.h
index 06e26cad884b..7e6696d7ab14 100644
--- a/libgcc/libgcc2.h
+++ b/libgcc/libgcc2.h
@@ -29,6 +29,9 @@ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
#pragma GCC visibility push(default)
#endif
+extern void __builtin_nested_func_ptr_created (void *, void *, void **);
+extern void __builtin_nested_func_ptr_deleted (void);
+
extern int __gcc_bcmp (const unsigned char *, const unsigned char *, size_t);
extern void __clear_cache (void *, void *);
extern void __eprintf (const char *, const char *, unsigned int, const char *)
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2023-10-22 13:01 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-10-22 13:01 [gcc r14-4823] libgcc: support heap-based trampolines Iain D Sandoe
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).