[ARM/FDPIC,2/4] linux-user: ARM-FDPIC: Add support of FDPIC for ARM.

Message ID 20180406151752.10854-3-christophe.lyon@st.com
State New
Headers show
Series
  • FDPIC ABI for ARM
Related show

Commit Message

Christophe Lyon April 6, 2018, 3:17 p.m.
Add FDPIC info into image_info structure since interpreter info is on
stack and needs to be saved to be accessed later on.

Co-Authored-By:  Mickaël Guêné <mickael.guene@st.com>
Signed-off-by: Christophe Lyon <christophe.lyon@st.com>


-- 
2.6.3

Comments

Peter Maydell April 13, 2018, 3:07 p.m. | #1
On 6 April 2018 at 16:17, Christophe Lyon <christophe.lyon@st.com> wrote:
> Add FDPIC info into image_info structure since interpreter info is on

> stack and needs to be saved to be accessed later on.

>

> Co-Authored-By:  Mickaël Guêné <mickael.guene@st.com>

> Signed-off-by: Christophe Lyon <christophe.lyon@st.com>

>

> diff --git a/linux-user/elfload.c b/linux-user/elfload.c

> index 7ba3795..363da67 100644

> --- a/linux-user/elfload.c

> +++ b/linux-user/elfload.c

> @@ -287,6 +287,23 @@ static inline void init_thread(struct target_pt_regs *regs,

>      /* For uClinux PIC binaries.  */

>      /* XXX: Linux does this only on ARM with no MMU (do we care ?) */

>      regs->uregs[10] = infop->start_data;

> +#ifdef CONFIG_USE_FDPIC

> +    /* Support ARM FDPIC.  */

> +    /* As described in the ABI document, r7 points to the loadmap info

> +     * prepared by the kernel. If an interpreter is needed, r8 points

> +     * to the interpreter loadmap and r9 points to the interpreter

> +     * PT_DYNAMIC info. If no interpreter is needed, r8 is zer0, and

> +     * r9 points to the main program PT_DYNAMIC info.  */

> +    regs->uregs[7] = infop->loadmap_addr;

> +    if (infop->interpreter_loadmap_addr) {

> +        /* Executable is dynamically loaded.  */

> +        regs->uregs[8] = infop->interpreter_loadmap_addr;

> +        regs->uregs[9] = infop->interpreter_pt_dynamic_addr;

> +    } else {

> +        regs->uregs[8] = 0;

> +        regs->uregs[9] = infop->pt_dynamic_addr;

> +    }


Is it really correct to set these registers always, and not only if
this is an FDPIC ELF ?

> +#endif

>  }


>  int load_elf_binary(struct linux_binprm *bprm, struct image_info *info);

> diff --git a/target/arm/cpu.h b/target/arm/cpu.h

> index 19a0c03..90c8ee1 100644

> --- a/target/arm/cpu.h

> +++ b/target/arm/cpu.h

> @@ -629,6 +629,12 @@ typedef struct CPUARMState {

>      const struct arm_boot_info *boot_info;

>      /* Store GICv3CPUState to access from this struct */

>      void *gicv3state;

> +

> +#if defined(CONFIG_USER_ONLY) && defined(CONFIG_USE_FDPIC)

> +    /* We need to know if we have an FDPIC binary to adapt signal

> +     * syscalls.  */

> +    int is_fdpic;


linux-user specific information shouldn't live in CPUARMState;
put it in the TaskState struct instead, perhaps.

> +#endif

>  } CPUARMState;

>

>  /**


thanks
-- PMM
Christophe Lyon April 16, 2018, 7:59 a.m. | #2
On 13/04/2018 17:07, Peter Maydell wrote:
> On 6 April 2018 at 16:17, Christophe Lyon <christophe.lyon@st.com> wrote:

>> Add FDPIC info into image_info structure since interpreter info is on

>> stack and needs to be saved to be accessed later on.

>>

>> Co-Authored-By:  Mickaël Guêné <mickael.guene@st.com>

>> Signed-off-by: Christophe Lyon <christophe.lyon@st.com>

>>

>> diff --git a/linux-user/elfload.c b/linux-user/elfload.c

>> index 7ba3795..363da67 100644

>> --- a/linux-user/elfload.c

>> +++ b/linux-user/elfload.c

>> @@ -287,6 +287,23 @@ static inline void init_thread(struct target_pt_regs *regs,

>>       /* For uClinux PIC binaries.  */

>>       /* XXX: Linux does this only on ARM with no MMU (do we care ?) */

>>       regs->uregs[10] = infop->start_data;

>> +#ifdef CONFIG_USE_FDPIC

>> +    /* Support ARM FDPIC.  */

>> +    /* As described in the ABI document, r7 points to the loadmap info

>> +     * prepared by the kernel. If an interpreter is needed, r8 points

>> +     * to the interpreter loadmap and r9 points to the interpreter

>> +     * PT_DYNAMIC info. If no interpreter is needed, r8 is zer0, and

>> +     * r9 points to the main program PT_DYNAMIC info.  */

>> +    regs->uregs[7] = infop->loadmap_addr;

>> +    if (infop->interpreter_loadmap_addr) {

>> +        /* Executable is dynamically loaded.  */

>> +        regs->uregs[8] = infop->interpreter_loadmap_addr;

>> +        regs->uregs[9] = infop->interpreter_pt_dynamic_addr;

>> +    } else {

>> +        regs->uregs[8] = 0;

>> +        regs->uregs[9] = infop->pt_dynamic_addr;

>> +    }

> 

> Is it really correct to set these registers always, and not only if

> this is an FDPIC ELF ?

> 

I need to check, but I used my FDPIC-enabled QEMU to run non-FDPIC
binaries and saw no problem.

>> +#endif

>>   }

> 

>>   int load_elf_binary(struct linux_binprm *bprm, struct image_info *info);

>> diff --git a/target/arm/cpu.h b/target/arm/cpu.h

>> index 19a0c03..90c8ee1 100644

>> --- a/target/arm/cpu.h

>> +++ b/target/arm/cpu.h

>> @@ -629,6 +629,12 @@ typedef struct CPUARMState {

>>       const struct arm_boot_info *boot_info;

>>       /* Store GICv3CPUState to access from this struct */

>>       void *gicv3state;

>> +

>> +#if defined(CONFIG_USER_ONLY) && defined(CONFIG_USE_FDPIC)

>> +    /* We need to know if we have an FDPIC binary to adapt signal

>> +     * syscalls.  */

>> +    int is_fdpic;

> 

> linux-user specific information shouldn't live in CPUARMState;

> put it in the TaskState struct instead, perhaps.

> 

OK, I'll have a look at that.

>> +#endif

>>   } CPUARMState;

>>

>>   /**

> 

> thanks

> -- PMM

> .

>

Patch

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 7ba3795..363da67 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -287,6 +287,23 @@  static inline void init_thread(struct target_pt_regs *regs,
     /* For uClinux PIC binaries.  */
     /* XXX: Linux does this only on ARM with no MMU (do we care ?) */
     regs->uregs[10] = infop->start_data;
+#ifdef CONFIG_USE_FDPIC
+    /* Support ARM FDPIC.  */
+    /* As described in the ABI document, r7 points to the loadmap info
+     * prepared by the kernel. If an interpreter is needed, r8 points
+     * to the interpreter loadmap and r9 points to the interpreter
+     * PT_DYNAMIC info. If no interpreter is needed, r8 is zer0, and
+     * r9 points to the main program PT_DYNAMIC info.  */
+    regs->uregs[7] = infop->loadmap_addr;
+    if (infop->interpreter_loadmap_addr) {
+        /* Executable is dynamically loaded.  */
+        regs->uregs[8] = infop->interpreter_loadmap_addr;
+        regs->uregs[9] = infop->interpreter_pt_dynamic_addr;
+    } else {
+        regs->uregs[8] = 0;
+        regs->uregs[9] = infop->pt_dynamic_addr;
+    }
+#endif
 }
 
 #define ELF_NREG    18
@@ -1692,6 +1709,11 @@  static abi_ulong loader_build_fdpic_loadmap(struct image_info *info, abi_ulong s
 }
 #endif
 
+int info_is_fdpic(struct image_info *info)
+{
+    return (info->personality == PER_LINUX_FDPIC);
+}
+
 static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc,
                                    struct elfhdr *exec,
                                    struct image_info *info,
@@ -1719,6 +1741,11 @@  static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc,
         if (interp_info) {
             interp_info->other_info = info;
             sp = loader_build_fdpic_loadmap(interp_info, sp);
+            info->interpreter_loadmap_addr = interp_info->loadmap_addr;
+            info->interpreter_pt_dynamic_addr = interp_info->pt_dynamic_addr;
+        } else {
+            info->interpreter_loadmap_addr = 0;
+            info->interpreter_pt_dynamic_addr = 0;
         }
     }
 #endif
diff --git a/linux-user/main.c b/linux-user/main.c
index ba09b7d..00810d6 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -4868,6 +4868,11 @@  int main(int argc, char **argv, char **envp)
             env->cp15.sctlr_el[i] |= SCTLR_EE;
         }
 #endif
+
+#if defined(CONFIG_USE_FDPIC)
+        /* Are we running an FDPIC binary?  */
+        env->is_fdpic = info_is_fdpic(info);
+#endif
     }
 #elif defined(TARGET_ARM)
     {
diff --git a/linux-user/qemu.h b/linux-user/qemu.h
index 192a0d2..7eaf9e9 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -56,6 +56,8 @@  struct image_info {
         uint16_t        nsegs;
         void           *loadsegs;
         abi_ulong       pt_dynamic_addr;
+        abi_ulong       interpreter_loadmap_addr;
+        abi_ulong       interpreter_pt_dynamic_addr;
         struct image_info *other_info;
 #endif
 };
@@ -182,6 +184,7 @@  abi_ulong loader_build_argptr(int envc, int argc, abi_ulong sp,
 int loader_exec(int fdexec, const char *filename, char **argv, char **envp,
              struct target_pt_regs * regs, struct image_info *infop,
              struct linux_binprm *);
+int info_is_fdpic(struct image_info *info);
 
 uint32_t get_elf_eflags(int fd);
 int load_elf_binary(struct linux_binprm *bprm, struct image_info *info);
diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index 19a0c03..90c8ee1 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -629,6 +629,12 @@  typedef struct CPUARMState {
     const struct arm_boot_info *boot_info;
     /* Store GICv3CPUState to access from this struct */
     void *gicv3state;
+
+#if defined(CONFIG_USER_ONLY) && defined(CONFIG_USE_FDPIC)
+    /* We need to know if we have an FDPIC binary to adapt signal
+     * syscalls.  */
+    int is_fdpic;
+#endif
 } CPUARMState;
 
 /**