Merge tag 'xtensa-20230523' of https://github.com/jcmvbkbc/linux-xtensa

Pull Xtensa fixes from Max Filippov:

 - fix signal delivery to FDPIC process

 - add __bswap{si,di}2 helpers

* tag 'xtensa-20230523' of https://github.com/jcmvbkbc/linux-xtensa:
  xtensa: add __bswap{si,di}2 helpers
  xtensa: fix signal delivery to FDPIC process

Author: torvalds

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];
 
@@ -373,29 +385,34 @@ 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.
 	 */
 
 	/* 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);

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);

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

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)

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)