@@ -100,6 +100,11 @@ struct elf32_hdr;
extern int elf_check_arch(const struct elf32_hdr *);
#define elf_check_arch elf_check_arch
+#define ELFOSABI_ARM_FDPIC 65 /* ARM FDPIC platform */
+#define elf_check_fdpic(x) ((x)->e_ident[EI_OSABI] == ELFOSABI_ARM_FDPIC)
+#define elf_check_const_displacement(x) ((x)->e_flags & EF_ARM_PIC)
+#define ELF_FDPIC_CORE_EFLAGS 0
+
#define vmcore_elf64_check_arch(x) (0)
extern int arm_elf_read_implies_exec(int);
@@ -120,6 +125,13 @@ int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs);
have no such handler. */
#define ELF_PLAT_INIT(_r, load_addr) (_r)->ARM_r0 = 0
+#define ELF_FDPIC_PLAT_INIT(_r, _exec_map_addr, _interp_map_addr, dynamic_addr) \
+ do { \
+ (_r)->ARM_r7 = _exec_map_addr; \
+ (_r)->ARM_r8 = _interp_map_addr; \
+ (_r)->ARM_r9 = dynamic_addr; \
+ } while(0)
+
extern void elf_set_personality(const struct elf32_hdr *);
#define SET_PERSONALITY(ex) elf_set_personality(&(ex))
@@ -33,6 +33,10 @@ typedef struct {
*/
typedef struct {
unsigned long end_brk;
+#ifdef CONFIG_BINFMT_ELF_FDPIC
+ unsigned long exec_fdpic_loadmap;
+ unsigned long interp_fdpic_loadmap;
+#endif
} mm_context_t;
#endif
@@ -31,6 +31,10 @@
#define PTRACE_SETVFPREGS 28
#define PTRACE_GETHBPREGS 29
#define PTRACE_SETHBPREGS 30
+#define PTRACE_GETFDPIC 31
+
+#define PTRACE_GETFDPIC_EXEC 0
+#define PTRACE_GETFDPIC_INTERP 1
/*
* PSR bits
@@ -23,6 +23,7 @@
#include <asm/vfp.h>
extern const unsigned long sigreturn_codes[7];
+extern const unsigned long sigreturn_fdpic_codes[6];
static unsigned long signal_return_offset;
@@ -323,9 +324,20 @@ 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;
unsigned long retcode;
int 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;
@@ -365,6 +377,20 @@ 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 process the function descriptor */
+ const unsigned long *opcodes = sigreturn_fdpic_codes;
+ opcodes += thumb + (thumb << 1);
+ if (__put_user(opcodes[0], rc) ||
+ __put_user(opcodes[1], rc+1) ||
+ __put_user(opcodes[2], rc+2) ||
+ __put_user(retcode, rc+3))
+ return 1;
+ /* Last word is not executed, hence 3 words to flush */
+ flush_icache_range((unsigned long)rc,
+ (unsigned long)(rc + 3));
+ retcode = (unsigned long)rc + thumb;
+ }
} else {
unsigned int idx = thumb << 1;
@@ -408,6 +434,8 @@ 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;
@@ -100,3 +100,25 @@ ARM_OK( swi #(__NR_rt_sigreturn)|(__NR_OABI_SYSCALL_BASE) )
.space 4
.size sigreturn_codes, . - sigreturn_codes
+
+#ifdef CONFIG_BINFMT_ELF_FDPIC
+
+ .global sigreturn_fdpic_codes
+ .type sigreturn_fdpic_codes, #object
+ .align
+sigreturn_fdpic_codes:
+
+ARM_OK( .arm )
+ARM_OK( ldr ip, [pc, #4] ) /* get function descriptor */
+ARM_OK( ldr r9, [ip, #4] ) /* setup GOT register */
+ARM_OK( ldr pc, [ip] ) /* branch to function */
+
+ .org sigreturn_fdpic_codes + 3*4
+ .thumb
+ ldr ip, [pc, #8] /* get function descriptor */
+ ldr r9, [ip, #4] /* setup GOT register */
+ ldr pc, [ip] /* branch to function */
+
+ .size sigreturn_fdpic_codes, . - sigreturn_fdpic_codes
+
+#endif
@@ -35,7 +35,7 @@ config ARCH_BINFMT_ELF_STATE
config BINFMT_ELF_FDPIC
bool "Kernel support for FDPIC ELF binaries"
default y
- depends on (FRV || BLACKFIN || (SUPERH32 && !MMU) || C6X)
+ depends on ((ARM && !MMU) || FRV || BLACKFIN || (SUPERH32 && !MMU) || C6X)
select ELFCORE
help
ELF FDPIC binaries are based on ELF, but allow the individual load
This includes the necessary code to recognise the FDPIC format on ARM, the handling of signal return code where function pointers are actually function descriptor pointers, and the ptrace command definitions used by the common ptrace code. Based on patches originally from Mickael Guene <mickael.guene@st.com>. Signed-off-by: Nicolas Pitre <nico@linaro.org> --- arch/arm/include/asm/elf.h | 12 ++++++++++++ arch/arm/include/asm/mmu.h | 4 ++++ arch/arm/include/uapi/asm/ptrace.h | 4 ++++ arch/arm/kernel/signal.c | 28 ++++++++++++++++++++++++++++ arch/arm/kernel/sigreturn_codes.S | 22 ++++++++++++++++++++++ fs/Kconfig.binfmt | 2 +- 6 files changed, 71 insertions(+), 1 deletion(-)