15 files changed, 199 insertions, 36 deletions

diff --git a/arch/arm/include/asm/elf.h b/arch/arm/include/asm/elf.h
index f13ae153fb24..ad0ca4f2ba13 100644
--- a/arch/arm/include/asm/elf.h
+++ b/arch/arm/include/asm/elf.h
@@ -100,10 +100,15 @@ 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(const struct elf32_hdr *, int);
-#define elf_read_implies_exec(ex,stk) arm_elf_read_implies_exec(&(ex), stk)
+extern int arm_elf_read_implies_exec(int);
+#define elf_read_implies_exec(ex,stk) arm_elf_read_implies_exec(stk)
 
 struct task_struct;
 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs);
@@ -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))
 
diff --git a/arch/arm/include/asm/mmu.h b/arch/arm/include/asm/mmu.h
index a5b47421059d..bdec37c6ac35 100644
--- a/arch/arm/include/asm/mmu.h
+++ b/arch/arm/include/asm/mmu.h
@@ -14,6 +14,10 @@ typedef struct {
 #ifdef CONFIG_VDSO
         unsigned long   vdso;
 #endif
+#ifdef CONFIG_BINFMT_ELF_FDPIC
+        unsigned long   exec_fdpic_loadmap;
+        unsigned long   interp_fdpic_loadmap;
+#endif
 } mm_context_t;
 
 #ifdef CONFIG_CPU_HAS_ASID
@@ -33,6 +37,10 @@ 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
diff --git a/arch/arm/include/asm/processor.h b/arch/arm/include/asm/processor.h
index c3d5fc124a05..338cbe0a18ef 100644
--- a/arch/arm/include/asm/processor.h
+++ b/arch/arm/include/asm/processor.h
@@ -47,15 +47,24 @@ struct thread_struct {
 
 #define INIT_THREAD  {  }
 
-#ifdef CONFIG_MMU
-#define nommu_start_thread(regs) do { } while (0)
-#else
-#define nommu_start_thread(regs) regs->ARM_r10 = current->mm->start_data
-#endif
-
 #define start_thread(regs,pc,sp)                                        \
 ({                                                                      \
+        unsigned long r7, r8, r9;                                       \
+                                                                        \
+        if (IS_ENABLED(CONFIG_BINFMT_ELF_FDPIC)) {                      \
+                r7 = regs->ARM_r7;                                      \
+                r8 = regs->ARM_r8;                                      \
+                r9 = regs->ARM_r9;                                      \
+        }                                                               \
         memset(regs->uregs, 0, sizeof(regs->uregs));                    \
+        if (IS_ENABLED(CONFIG_BINFMT_ELF_FDPIC) &&                      \
+            current->personality & FDPIC_FUNCPTRS) {                    \
+                regs->ARM_r7 = r7;                                      \
+                regs->ARM_r8 = r8;                                      \
+                regs->ARM_r9 = r9;                                      \
+                regs->ARM_r10 = current->mm->start_data;                \
+        } else if (!IS_ENABLED(CONFIG_MMU))                             \
+                regs->ARM_r10 = current->mm->start_data;                \
         if (current->personality & ADDR_LIMIT_32BIT)                    \
                 regs->ARM_cpsr = USR_MODE;                              \
         else                                                            \
@@ -65,7 +74,6 @@ struct thread_struct {
         regs->ARM_cpsr |= PSR_ENDSTATE;                                 \
         regs->ARM_pc = pc & ~1;         /* pc */                        \
         regs->ARM_sp = sp;              /* sp */                        \
-        nommu_start_thread(regs);                                       \
 })
 
 /* Forward declaration, a strange C thing */
diff --git a/arch/arm/include/asm/ucontext.h b/arch/arm/include/asm/ucontext.h
index 921d8274855c..b42c75ae0d19 100644
--- a/arch/arm/include/asm/ucontext.h
+++ b/arch/arm/include/asm/ucontext.h
@@ -2,6 +2,7 @@
 #define _ASMARM_UCONTEXT_H
 
 #include <asm/fpstate.h>
+#include <asm/user.h>
 
 /*
  * struct sigcontext only has room for the basic registers, but struct
diff --git a/arch/arm/include/uapi/asm/ptrace.h b/arch/arm/include/uapi/asm/ptrace.h
index 5af0ed1b825a..3173eb9751fd 100644
--- a/arch/arm/include/uapi/asm/ptrace.h
+++ b/arch/arm/include/uapi/asm/ptrace.h
@@ -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
diff --git a/arch/arm/include/uapi/asm/unistd.h b/arch/arm/include/uapi/asm/unistd.h
index 28bd456494a3..575b25fc29c6 100644
--- a/arch/arm/include/uapi/asm/unistd.h
+++ b/arch/arm/include/uapi/asm/unistd.h
@@ -35,5 +35,6 @@
 #define __ARM_NR_usr26                  (__ARM_NR_BASE+3)
 #define __ARM_NR_usr32                  (__ARM_NR_BASE+4)
 #define __ARM_NR_set_tls                (__ARM_NR_BASE+5)
+#define __ARM_NR_get_tls                (__ARM_NR_BASE+6)
 
 #endif /* _UAPI__ASM_ARM_UNISTD_H */
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/elf.c b/arch/arm/kernel/elf.c
index d0d1e83150c9..569e69ece5ca 100644
--- a/arch/arm/kernel/elf.c
+++ b/arch/arm/kernel/elf.c
@@ -3,6 +3,7 @@
 #include <linux/personality.h>
 #include <linux/binfmts.h>
 #include <linux/elf.h>
+#include <linux/elf-fdpic.h>
 #include <asm/system_info.h>
 
 int elf_check_arch(const struct elf32_hdr *x)
@@ -80,7 +81,7 @@ EXPORT_SYMBOL(elf_set_personality);
  *  - the binary requires an executable stack
  *  - we're running on a CPU which doesn't support NX.
  */
-int arm_elf_read_implies_exec(const struct elf32_hdr *x, int executable_stack)
+int arm_elf_read_implies_exec(int executable_stack)
 {
         if (executable_stack != EXSTACK_DISABLE_X)
                 return 1;
@@ -89,3 +90,24 @@ int arm_elf_read_implies_exec(const struct elf32_hdr *x, int executable_stack)
         return 0;
 }
 EXPORT_SYMBOL(arm_elf_read_implies_exec);
+
+#if defined(CONFIG_MMU) && defined(CONFIG_BINFMT_ELF_FDPIC)
+
+void elf_fdpic_arch_lay_out_mm(struct elf_fdpic_params *exec_params,
+                               struct elf_fdpic_params *interp_params,
+                               unsigned long *start_stack,
+                               unsigned long *start_brk)
+{
+        elf_set_personality(&exec_params->hdr);
+
+        exec_params->load_addr = 0x8000;
+        interp_params->load_addr = ELF_ET_DYN_BASE;
+        *start_stack = TASK_SIZE - SZ_16M;
+
+        if ((exec_params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) == ELF_FDPIC_FLAG_INDEPENDENT) {
+                exec_params->flags &= ~ELF_FDPIC_FLAG_ARRANGEMENT;
+                exec_params->flags |= ELF_FDPIC_FLAG_CONSTDISP;
+        }
+}
+
+#endif
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index e2de50bf8742..237973492479 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -19,11 +19,12 @@
 #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;
 
@@ -172,15 +173,6 @@ 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)
 {
@@ -366,9 +358,20 @@ 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;
 
@@ -408,9 +411,26 @@ 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;
 
@@ -422,6 +442,7 @@ 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;
@@ -441,7 +462,7 @@ 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;
                 }
@@ -451,6 +472,8 @@ 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
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 948c648fea00..43c0560f7b2d 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -647,6 +647,9 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs)
                 set_tls(regs->ARM_r0);
                 return 0;
 
+        case NR(get_tls):
+                return current_thread_info()->tp_value[0];
+
         default:
                 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS
                    if not implemented, rather than raising SIGILL.  This
diff --git a/fs/Kconfig.binfmt b/fs/Kconfig.binfmt
index b2f82cf6bf86..58c2bbd385ad 100644
--- a/fs/Kconfig.binfmt
+++ b/fs/Kconfig.binfmt
@@ -34,8 +34,8 @@ 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)
+        default y if !BINFMT_ELF
+        depends on (ARM || FRV || BLACKFIN || (SUPERH32 && !MMU) || C6X)
         select ELFCORE
         help
           ELF FDPIC binaries are based on ELF, but allow the individual load
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 73b01e474fdc..e4f7ef8294ac 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -51,6 +51,11 @@
 #define user_siginfo_t siginfo_t
 #endif
 
+/* That's for binfmt_elf_fdpic to deal with */
+#ifndef elf_check_fdpic
+#define elf_check_fdpic(ex) false
+#endif
+
 static int load_elf_binary(struct linux_binprm *bprm);
 static unsigned long elf_map(struct file *, unsigned long, struct elf_phdr *,
                                 int, int, unsigned long);
@@ -541,7 +546,8 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
         if (interp_elf_ex->e_type != ET_EXEC &&
             interp_elf_ex->e_type != ET_DYN)
                 goto out;
-        if (!elf_check_arch(interp_elf_ex))
+        if (!elf_check_arch(interp_elf_ex) ||
+            elf_check_fdpic(interp_elf_ex))
                 goto out;
         if (!interpreter->f_op->mmap)
                 goto out;
@@ -718,6 +724,8 @@ static int load_elf_binary(struct linux_binprm *bprm)
                 goto out;
         if (!elf_check_arch(&loc->elf_ex))
                 goto out;
+        if (elf_check_fdpic(&loc->elf_ex))
+                goto out;
         if (!bprm->file->f_op->mmap)
                 goto out;
 
@@ -817,7 +825,8 @@ static int load_elf_binary(struct linux_binprm *bprm)
                 if (memcmp(loc->interp_elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
                         goto out_free_dentry;
                 /* Verify the interpreter has a valid arch */
-                if (!elf_check_arch(&loc->interp_elf_ex))
+                if (!elf_check_arch(&loc->interp_elf_ex) ||
+                    elf_check_fdpic(&loc->interp_elf_ex))
                         goto out_free_dentry;
 
                 /* Load the interpreter program headers */
@@ -1190,6 +1199,8 @@ static int load_elf_library(struct file *file)
         if (elf_ex.e_type != ET_EXEC || elf_ex.e_phnum > 2 ||
             !elf_check_arch(&elf_ex) || !file->f_op->mmap)
                 goto out;
+        if (elf_check_fdpic(&elf_ex))
+                goto out;
 
         /* Now read in all of the header information */
 
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index e70c039ac190..5429b035e249 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -378,6 +378,11 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
                                  executable_stack);
         if (retval < 0)
                 goto error;
+#ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
+        retval = arch_setup_additional_pages(bprm, !!interpreter_name);
+        if (retval < 0)
+                goto error;
+#endif
 #endif
 
         /* load the executable and interpreter into memory */
@@ -831,6 +836,9 @@ static int elf_fdpic_map_file(struct elf_fdpic_params *params,
                         if (phdr->p_vaddr >= seg->p_vaddr &&
                             phdr->p_vaddr + phdr->p_memsz <=
                             seg->p_vaddr + seg->p_memsz) {
+                                Elf32_Dyn __user *dyn;
+                                Elf32_Sword d_tag;
+
                                 params->dynamic_addr =
                                         (phdr->p_vaddr - seg->p_vaddr) +
                                         seg->addr;
@@ -843,8 +851,9 @@ static int elf_fdpic_map_file(struct elf_fdpic_params *params,
                                         goto dynamic_error;
 
                                 tmp = phdr->p_memsz / sizeof(Elf32_Dyn);
-                                if (((Elf32_Dyn *)
-                                     params->dynamic_addr)[tmp - 1].d_tag != 0)
+                                dyn = (Elf32_Dyn __user *)params->dynamic_addr;
+                                __get_user(d_tag, &dyn[tmp - 1].d_tag);
+                                if (d_tag != 0)
                                         goto dynamic_error;
                                 break;
                         }