[PATCH] linux-user: add support for xtensa FDPIC

[PATCH] linux-user: add support for xtensa FDPIC

[Max Filippov]

Define xtensa-specific info_is_fdpic and fill in FDPIC-specific
registers in the xtensa version of init_thread.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 include/elf.h        |  1 +
 linux-user/elfload.c | 16 +++++++++++++++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/include/elf.h b/include/elf.h
index 8bf1e72720d5..e8bfe38a9fbd 100644
--- a/include/elf.h
+++ b/include/elf.h
@@ -1619,6 +1619,7 @@ typedef struct elf64_shdr {
 #define ELFOSABI_MODESTO        11      /* Novell Modesto.  */
 #define ELFOSABI_OPENBSD        12      /* OpenBSD.  */
 #define ELFOSABI_ARM_FDPIC      65      /* ARM FDPIC */
+#define ELFOSABI_XTENSA_FDPIC   65      /* Xtensa FDPIC */
 #define ELFOSABI_ARM            97      /* ARM */
 #define ELFOSABI_STANDALONE     255     /* Standalone (embedded) application */
 
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 5928c14dfc97..150d1d450396 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -1748,6 +1748,15 @@ static inline void init_thread(struct target_pt_regs *regs,
     regs->windowstart = 1;
     regs->areg[1] = infop->start_stack;
     regs->pc = infop->entry;
+    if (info_is_fdpic(infop)) {
+        regs->areg[4] = infop->loadmap_addr;
+        regs->areg[5] = infop->interpreter_loadmap_addr;
+        if (infop->interpreter_loadmap_addr) {
+            regs->areg[6] = infop->interpreter_pt_dynamic_addr;
+        } else {
+            regs->areg[6] = infop->pt_dynamic_addr;
+        }
+    }
 }
 
 /* See linux kernel: arch/xtensa/include/asm/elf.h.  */
@@ -2207,11 +2216,16 @@ static void zero_bss(abi_ulong elf_bss, abi_ulong last_bss, int prot)
     }
 }
 
-#ifdef TARGET_ARM
+#if defined(TARGET_ARM)
 static int elf_is_fdpic(struct elfhdr *exec)
 {
     return exec->e_ident[EI_OSABI] == ELFOSABI_ARM_FDPIC;
 }
+#elif defined(TARGET_XTENSA)
+static int elf_is_fdpic(struct elfhdr *exec)
+{
+    return exec->e_ident[EI_OSABI] == ELFOSABI_XTENSA_FDPIC;
+}
 #else
 /* Default implementation, always false.  */
 static int elf_is_fdpic(struct elfhdr *exec)
-- 
2.30.2

Re: [PATCH] linux-user: add support for xtensa FDPIC

[Laurent Vivier]

Le 05/02/2023 à 07:12, Max Filippov a écrit :
> Define xtensa-specific info_is_fdpic and fill in FDPIC-specific
> registers in the xtensa version of init_thread.
> 
> Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
> ---
>   include/elf.h        |  1 +
>   linux-user/elfload.c | 16 +++++++++++++++-
>   2 files changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/include/elf.h b/include/elf.h
> index 8bf1e72720d5..e8bfe38a9fbd 100644
> --- a/include/elf.h
> +++ b/include/elf.h
> @@ -1619,6 +1619,7 @@ typedef struct elf64_shdr {
>   #define ELFOSABI_MODESTO        11      /* Novell Modesto.  */
>   #define ELFOSABI_OPENBSD        12      /* OpenBSD.  */
>   #define ELFOSABI_ARM_FDPIC      65      /* ARM FDPIC */
> +#define ELFOSABI_XTENSA_FDPIC   65      /* Xtensa FDPIC */
>   #define ELFOSABI_ARM            97      /* ARM */
>   #define ELFOSABI_STANDALONE     255     /* Standalone (embedded) application */
>   
> diff --git a/linux-user/elfload.c b/linux-user/elfload.c
> index 5928c14dfc97..150d1d450396 100644
> --- a/linux-user/elfload.c
> +++ b/linux-user/elfload.c
> @@ -1748,6 +1748,15 @@ static inline void init_thread(struct target_pt_regs *regs,
>       regs->windowstart = 1;
>       regs->areg[1] = infop->start_stack;
>       regs->pc = infop->entry;
> +    if (info_is_fdpic(infop)) {
> +        regs->areg[4] = infop->loadmap_addr;
> +        regs->areg[5] = infop->interpreter_loadmap_addr;
> +        if (infop->interpreter_loadmap_addr) {
> +            regs->areg[6] = infop->interpreter_pt_dynamic_addr;
> +        } else {
> +            regs->areg[6] = infop->pt_dynamic_addr;
> +        }
> +    }
>   }
>   
>   /* See linux kernel: arch/xtensa/include/asm/elf.h.  */
> @@ -2207,11 +2216,16 @@ static void zero_bss(abi_ulong elf_bss, abi_ulong last_bss, int prot)
>       }
>   }
>   
> -#ifdef TARGET_ARM
> +#if defined(TARGET_ARM)
>   static int elf_is_fdpic(struct elfhdr *exec)
>   {
>       return exec->e_ident[EI_OSABI] == ELFOSABI_ARM_FDPIC;
>   }
> +#elif defined(TARGET_XTENSA)
> +static int elf_is_fdpic(struct elfhdr *exec)
> +{
> +    return exec->e_ident[EI_OSABI] == ELFOSABI_XTENSA_FDPIC;
> +}
>   #else
>   /* Default implementation, always false.  */
>   static int elf_is_fdpic(struct elfhdr *exec)

Applied to my linux-user-for-8.0 branch.

Thanks,
Laurent