From 9c2cc74fb31ec76b8b118c97041a6a154a3ff219 Mon Sep 17 00:00:00 2001
From: Max Filippov <jcmvbkbc@gmail.com>
Date: Tue, 2 May 2023 03:20:47 -0700
Subject: [PATCH 1/2] xtensa: fix signal delivery to FDPIC process
Fetch function descriptor pointed to by the signal handler pointer from
userspace on signal delivery and function pointer pointed to by the
sa_restorer on return from the signal handler.
Cc: stable@vger.kernel.org
Fixes: e3ddb8bbe0f8 ("xtensa: add FDPIC and static PIE support for noMMU")
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
arch/xtensa/kernel/signal.c | 35 +++++++++++++++++++++++++++--------
1 file changed, 27 insertions(+), 8 deletions(-)
diff --git a/arch/xtensa/kernel/signal.c b/arch/xtensa/kernel/signal.c
index 876d5df157ed9..5c01d7e70d90d 100644
--- a/arch/xtensa/kernel/signal.c
+++ b/arch/xtensa/kernel/signal.c
@@ -343,7 +343,19 @@ static int setup_frame(struct ksignal *ksig, sigset_t *set,
struct rt_sigframe *frame;
int err = 0, sig = ksig->sig;
unsigned long sp, ra, tp, ps;
+ unsigned long handler = (unsigned long)ksig->ka.sa.sa_handler;
+ unsigned long handler_fdpic_GOT = 0;
unsigned int base;
+ bool fdpic = IS_ENABLED(CONFIG_BINFMT_ELF_FDPIC) &&
+ (current->personality & FDPIC_FUNCPTRS);
+
+ if (fdpic) {
+ unsigned long __user *fdpic_func_desc =
+ (unsigned long __user *)handler;
+ if (__get_user(handler, &fdpic_func_desc[0]) ||
+ __get_user(handler_fdpic_GOT, &fdpic_func_desc[1]))
+ return -EFAULT;
+ }
sp = regs->areg[1];
@@ -373,20 +385,26 @@ static int setup_frame(struct ksignal *ksig, sigset_t *set,
err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
if (ksig->ka.sa.sa_flags & SA_RESTORER) {
- ra = (unsigned long)ksig->ka.sa.sa_restorer;
+ if (fdpic) {
+ unsigned long __user *fdpic_func_desc =
+ (unsigned long __user *)ksig->ka.sa.sa_restorer;
+
+ err |= __get_user(ra, fdpic_func_desc);
+ } else {
+ ra = (unsigned long)ksig->ka.sa.sa_restorer;
+ }
} else {
/* Create sys_rt_sigreturn syscall in stack frame */
err |= gen_return_code(frame->retcode);
-
- if (err) {
- return -EFAULT;
- }
ra = (unsigned long) frame->retcode;
}
- /*
+ if (err)
+ return -EFAULT;
+
+ /*
* Create signal handler execution context.
* Return context not modified until this point.
*/
@@ -394,8 +412,7 @@ static int setup_frame(struct ksignal *ksig, sigset_t *set,
/* Set up registers for signal handler; preserve the threadptr */
tp = regs->threadptr;
ps = regs->ps;
- start_thread(regs, (unsigned long) ksig->ka.sa.sa_handler,
- (unsigned long) frame);
+ start_thread(regs, handler, (unsigned long)frame);
/* Set up a stack frame for a call4 if userspace uses windowed ABI */
if (ps & PS_WOE_MASK) {
@@ -413,6 +430,8 @@ static int setup_frame(struct ksignal *ksig, sigset_t *set,
regs->areg[base + 4] = (unsigned long) &frame->uc;
regs->threadptr = tp;
regs->ps = ps;
+ if (fdpic)
+ regs->areg[base + 11] = handler_fdpic_GOT;
pr_debug("SIG rt deliver (%s:%d): signal=%d sp=%p pc=%08lx\n",
current->comm, current->pid, sig, frame, regs->pc);
From 034f4a7877c32a8efd6beee4d71ed14e424499a9 Mon Sep 17 00:00:00 2001
From: Max Filippov <jcmvbkbc@gmail.com>
Date: Sat, 6 May 2023 17:10:36 -0700
Subject: [PATCH 2/2] xtensa: add __bswap{si,di}2 helpers
gcc-13 may generate calls for __bswap{si,di}2. This breaks the kernel
build when optimization for size is selected. Add __bswap{si,di}2
helpers to fix that.
Cc: stable@vger.kernel.org
Fixes: 19c5699f9aff ("xtensa: don't link with libgcc")
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
arch/xtensa/kernel/xtensa_ksyms.c | 4 ++++
arch/xtensa/lib/Makefile | 2 +-
arch/xtensa/lib/bswapdi2.S | 21 +++++++++++++++++++++
arch/xtensa/lib/bswapsi2.S | 16 ++++++++++++++++
4 files changed, 42 insertions(+), 1 deletion(-)
create mode 100644 arch/xtensa/lib/bswapdi2.S
create mode 100644 arch/xtensa/lib/bswapsi2.S
diff --git a/arch/xtensa/kernel/xtensa_ksyms.c b/arch/xtensa/kernel/xtensa_ksyms.c
index 2a31b1ab0c9f2..17a7ef86fd0dd 100644
--- a/arch/xtensa/kernel/xtensa_ksyms.c
+++ b/arch/xtensa/kernel/xtensa_ksyms.c
@@ -56,6 +56,8 @@ EXPORT_SYMBOL(empty_zero_page);
*/
extern long long __ashrdi3(long long, int);
extern long long __ashldi3(long long, int);
+extern long long __bswapdi2(long long);
+extern int __bswapsi2(int);
extern long long __lshrdi3(long long, int);
extern int __divsi3(int, int);
extern int __modsi3(int, int);
@@ -66,6 +68,8 @@ extern unsigned long long __umulsidi3(unsigned int, unsigned int);
EXPORT_SYMBOL(__ashldi3);
EXPORT_SYMBOL(__ashrdi3);
+EXPORT_SYMBOL(__bswapdi2);
+EXPORT_SYMBOL(__bswapsi2);
EXPORT_SYMBOL(__lshrdi3);
EXPORT_SYMBOL(__divsi3);
EXPORT_SYMBOL(__modsi3);
diff --git a/arch/xtensa/lib/Makefile b/arch/xtensa/lib/Makefile
index 7ecef0519a27c..c9c2614188f74 100644
--- a/arch/xtensa/lib/Makefile
+++ b/arch/xtensa/lib/Makefile
@@ -4,7 +4,7 @@
#
lib-y += memcopy.o memset.o checksum.o \
- ashldi3.o ashrdi3.o lshrdi3.o \
+ ashldi3.o ashrdi3.o bswapdi2.o bswapsi2.o lshrdi3.o \
divsi3.o udivsi3.o modsi3.o umodsi3.o mulsi3.o umulsidi3.o \
usercopy.o strncpy_user.o strnlen_user.o
lib-$(CONFIG_PCI) += pci-auto.o
diff --git a/arch/xtensa/lib/bswapdi2.S b/arch/xtensa/lib/bswapdi2.S
new file mode 100644
index 0000000000000..d8e52e05eba66
--- /dev/null
+++ b/arch/xtensa/lib/bswapdi2.S
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later WITH GCC-exception-2.0 */
+#include <linux/linkage.h>
+#include <asm/asmmacro.h>
+#include <asm/core.h>
+
+ENTRY(__bswapdi2)
+
+ abi_entry_default
+ ssai 8
+ srli a4, a2, 16
+ src a4, a4, a2
+ src a4, a4, a4
+ src a4, a2, a4
+ srli a2, a3, 16
+ src a2, a2, a3
+ src a2, a2, a2
+ src a2, a3, a2
+ mov a3, a4
+ abi_ret_default
+
+ENDPROC(__bswapdi2)
diff --git a/arch/xtensa/lib/bswapsi2.S b/arch/xtensa/lib/bswapsi2.S
new file mode 100644
index 0000000000000..9c1de1344f79a
--- /dev/null
+++ b/arch/xtensa/lib/bswapsi2.S
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later WITH GCC-exception-2.0 */
+#include <linux/linkage.h>
+#include <asm/asmmacro.h>
+#include <asm/core.h>
+
+ENTRY(__bswapsi2)
+
+ abi_entry_default
+ ssai 8
+ srli a3, a2, 16
+ src a3, a3, a2
+ src a3, a3, a3
+ src a2, a2, a3
+ abi_ret_default
+
+ENDPROC(__bswapsi2)