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-rw-r--r--arch/arm/kernel/asm-offsets.c4
-rw-r--r--arch/arm/kernel/signal.c53
-rw-r--r--arch/arm/kernel/signal.h11
-rw-r--r--arch/arm/kernel/sigreturn_codes.S56
4 files changed, 104 insertions, 20 deletions
diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c
index 608008229c7d..13c155850822 100644
--- a/arch/arm/kernel/asm-offsets.c
+++ b/arch/arm/kernel/asm-offsets.c
@@ -28,6 +28,7 @@
#include <asm/vdso_datapage.h>
#include <asm/hardware/cache-l2x0.h>
#include <linux/kbuild.h>
+#include "signal.h"
/*
* Make sure that the compiler and target are compatible.
@@ -112,6 +113,9 @@ int main(void)
DEFINE(SVC_ADDR_LIMIT, offsetof(struct svc_pt_regs, addr_limit));
DEFINE(SVC_REGS_SIZE, sizeof(struct svc_pt_regs));
BLANK();
+ DEFINE(SIGFRAME_RC3_OFFSET, offsetof(struct sigframe, retcode[3]));
+ DEFINE(RT_SIGFRAME_RC3_OFFSET, offsetof(struct rt_sigframe, sig.retcode[3]));
+ BLANK();
#ifdef CONFIG_CACHE_L2X0
DEFINE(L2X0_R_PHY_BASE, offsetof(struct l2x0_regs, phy_base));
DEFINE(L2X0_R_AUX_CTRL, offsetof(struct l2x0_regs, aux_ctrl));
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index 5814298ef0b7..1f3574ec4fad 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -18,11 +18,12 @@
#include <asm/elf.h>
#include <asm/cacheflush.h>
#include <asm/traps.h>
-#include <asm/ucontext.h>
#include <asm/unistd.h>
#include <asm/vfp.h>
-extern const unsigned long sigreturn_codes[7];
+#include "signal.h"
+
+extern const unsigned long sigreturn_codes[17];
static unsigned long signal_return_offset;
@@ -171,15 +172,6 @@ static int restore_vfp_context(char __user **auxp)
/*
* Do a signal return; undo the signal stack. These are aligned to 64-bit.
*/
-struct sigframe {
- struct ucontext uc;
- unsigned long retcode[2];
-};
-
-struct rt_sigframe {
- struct siginfo info;
- struct sigframe sig;
-};
static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
{
@@ -365,9 +357,20 @@ setup_return(struct pt_regs *regs, struct ksignal *ksig,
unsigned long __user *rc, void __user *frame)
{
unsigned long handler = (unsigned long)ksig->ka.sa.sa_handler;
+ unsigned long handler_fdpic_GOT = 0;
unsigned long retcode;
- int thumb = 0;
+ unsigned int idx, thumb = 0;
unsigned long cpsr = regs->ARM_cpsr & ~(PSR_f | PSR_E_BIT);
+ 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 1;
+ }
cpsr |= PSR_ENDSTATE;
@@ -407,9 +410,26 @@ setup_return(struct pt_regs *regs, struct ksignal *ksig,
if (ksig->ka.sa.sa_flags & SA_RESTORER) {
retcode = (unsigned long)ksig->ka.sa.sa_restorer;
+ if (fdpic) {
+ /*
+ * We need code to load the function descriptor.
+ * That code follows the standard sigreturn code
+ * (6 words), and is made of 3 + 2 words for each
+ * variant. The 4th copied word is the actual FD
+ * address that the assembly code expects.
+ */
+ idx = 6 + thumb * 3;
+ if (ksig->ka.sa.sa_flags & SA_SIGINFO)
+ idx += 5;
+ if (__put_user(sigreturn_codes[idx], rc ) ||
+ __put_user(sigreturn_codes[idx+1], rc+1) ||
+ __put_user(sigreturn_codes[idx+2], rc+2) ||
+ __put_user(retcode, rc+3))
+ return 1;
+ goto rc_finish;
+ }
} else {
- unsigned int idx = thumb << 1;
-
+ idx = thumb << 1;
if (ksig->ka.sa.sa_flags & SA_SIGINFO)
idx += 3;
@@ -421,6 +441,7 @@ setup_return(struct pt_regs *regs, struct ksignal *ksig,
__put_user(sigreturn_codes[idx+1], rc+1))
return 1;
+rc_finish:
#ifdef CONFIG_MMU
if (cpsr & MODE32_BIT) {
struct mm_struct *mm = current->mm;
@@ -440,7 +461,7 @@ setup_return(struct pt_regs *regs, struct ksignal *ksig,
* the return code written onto the stack.
*/
flush_icache_range((unsigned long)rc,
- (unsigned long)(rc + 2));
+ (unsigned long)(rc + 3));
retcode = ((unsigned long)rc) + thumb;
}
@@ -450,6 +471,8 @@ setup_return(struct pt_regs *regs, struct ksignal *ksig,
regs->ARM_sp = (unsigned long)frame;
regs->ARM_lr = retcode;
regs->ARM_pc = handler;
+ if (fdpic)
+ regs->ARM_r9 = handler_fdpic_GOT;
regs->ARM_cpsr = cpsr;
return 0;
diff --git a/arch/arm/kernel/signal.h b/arch/arm/kernel/signal.h
new file mode 100644
index 000000000000..b7b838b05229
--- /dev/null
+++ b/arch/arm/kernel/signal.h
@@ -0,0 +1,11 @@
+#include <asm/ucontext.h>
+
+struct sigframe {
+ struct ucontext uc;
+ unsigned long retcode[4];
+};
+
+struct rt_sigframe {
+ struct siginfo info;
+ struct sigframe sig;
+};
diff --git a/arch/arm/kernel/sigreturn_codes.S b/arch/arm/kernel/sigreturn_codes.S
index b84d0cb13682..2c7b22e32152 100644
--- a/arch/arm/kernel/sigreturn_codes.S
+++ b/arch/arm/kernel/sigreturn_codes.S
@@ -14,6 +14,8 @@
* GNU General Public License for more details.
*/
+#include <asm/assembler.h>
+#include <asm/asm-offsets.h>
#include <asm/unistd.h>
/*
@@ -51,6 +53,17 @@ ARM_OK( .arm )
.thumb
.endm
+ .macro arm_fdpic_slot n
+ .org sigreturn_codes + 24 + 20 * (\n)
+ARM_OK( .arm )
+ .endm
+
+ .macro thumb_fdpic_slot n
+ .org sigreturn_codes + 24 + 20 * (\n) + 12
+ .thumb
+ .endm
+
+
#if __LINUX_ARM_ARCH__ <= 4
/*
* Note we manually set minimally required arch that supports
@@ -90,13 +103,46 @@ ARM_OK( swi #(__NR_rt_sigreturn)|(__NR_OABI_SYSCALL_BASE) )
movs r7, #(__NR_rt_sigreturn - __NR_SYSCALL_BASE)
swi #0
+ /* ARM sigreturn restorer FDPIC bounce code snippet */
+ arm_fdpic_slot 0
+ARM_OK( ldr r3, [sp, #SIGFRAME_RC3_OFFSET] )
+ARM_OK( ldmia r3, {r3, r9} )
+#ifdef CONFIG_ARM_THUMB
+ARM_OK( bx r3 )
+#else
+ARM_OK( ret r3 )
+#endif
+
+ /* Thumb sigreturn restorer FDPIC bounce code snippet */
+ thumb_fdpic_slot 0
+ ldr r3, [sp, #SIGFRAME_RC3_OFFSET]
+ ldmia r3, {r2, r3}
+ mov r9, r3
+ bx r2
+
+ /* ARM sigreturn_rt restorer FDPIC bounce code snippet */
+ arm_fdpic_slot 1
+ARM_OK( ldr r3, [sp, #RT_SIGFRAME_RC3_OFFSET] )
+ARM_OK( ldmia r3, {r3, r9} )
+#ifdef CONFIG_ARM_THUMB
+ARM_OK( bx r3 )
+#else
+ARM_OK( ret r3 )
+#endif
+
+ /* Thumb sigreturn_rt restorer FDPIC bounce code snippet */
+ thumb_fdpic_slot 1
+ ldr r3, [sp, #RT_SIGFRAME_RC3_OFFSET]
+ ldmia r3, {r2, r3}
+ mov r9, r3
+ bx r2
+
/*
- * Note on addtional space: setup_return in signal.c
- * algorithm uses two words copy regardless whether
- * it is thumb case or not, so we need additional
- * word after real last entry.
+ * Note on additional space: setup_return in signal.c
+ * always copies the same number of words regardless whether
+ * it is thumb case or not, so we need one additional padding
+ * word after the last entry.
*/
- arm_slot 2
.space 4
.size sigreturn_codes, . - sigreturn_codes
generated by cgit (git 2.34.1) at 2024-06-13 19:33:53 +0000