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authorPaul Burton <paul.burton@imgtec.com>2014-09-11 08:30:16 +0100
committerRalf Baechle <ralf@linux-mips.org>2014-11-24 07:45:02 +0100
commit774c105ed8d791b709b40082d107f5bb40254374 (patch)
treeeeb98c210029fbba0482a035f897e60d9cf43aa4 /fs/Kconfig.binfmt
parenta9d9ef133f443ae91d2d24594e63714c0b53d09f (diff)
binfmt_elf: allow arch code to examine PT_LOPROC ... PT_HIPROC headers
MIPS is introducing new variants of its O32 ABI which differ in their handling of floating point, in order to enable a gradual transition towards a world where mips32 binaries can take advantage of new hardware features only available when configured for certain FP modes. In order to do this ELF binaries are being augmented with a new section that indicates, amongst other things, the FP mode requirements of the binary. The presence & location of such a section is indicated by a program header in the PT_LOPROC ... PT_HIPROC range. In order to allow the MIPS architecture code to examine the program header & section in question, pass all program headers in this range to an architecture-specific arch_elf_pt_proc function. This function may return an error if the header is deemed invalid or unsuitable for the system, in which case that error will be returned from load_elf_binary and upwards through the execve syscall. A means is required for the architecture code to make a decision once it is known that all such headers have been seen, but before it is too late to return from an execve syscall. For this purpose the arch_check_elf function is added, and called once, after all PT_LOPROC to PT_HIPROC headers have been passed to arch_elf_pt_proc but before the code which invoked execve has been lost. This enables the architecture code to make a decision based upon all the headers present in an ELF binary and its interpreter, as is required to forbid conflicting FP ABI requirements between an ELF & its interpreter. In order to allow data to be stored throughout the calls to the above functions, struct arch_elf_state is introduced. Finally a variant of the SET_PERSONALITY macro is introduced which accepts a pointer to the struct arch_elf_state, allowing it to act based upon state observed from the architecture specific program headers. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/7679/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'fs/Kconfig.binfmt')
-rw-r--r--fs/Kconfig.binfmt3
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/Kconfig.binfmt b/fs/Kconfig.binfmt
index 370b24cee4d8..c055d56ec63d 100644
--- a/fs/Kconfig.binfmt
+++ b/fs/Kconfig.binfmt
@@ -30,6 +30,9 @@ config COMPAT_BINFMT_ELF
config ARCH_BINFMT_ELF_RANDOMIZE_PIE
bool
+config ARCH_BINFMT_ELF_STATE
+ bool
+
config BINFMT_ELF_FDPIC
bool "Kernel support for FDPIC ELF binaries"
default y