This series introduces support for reading the FP mode requirements of ELF binaries from their .MIPS.abiflags section when present, and configuring the system appropriately. The motivation for these new ABIs is to enable O32 binaries to operate with a 64b FPU (Status.FR=1) and therefore to run on systems where that is the only FPU available, allow use of MSA & do so without rebuilding the world. For further details on the new ABIs please see: https://dmz-portal.mips.com/wiki/MIPS_O32_ABI_-_FR0_and_FR1_Interlinking The first 3 patches of the series extend binfmt_elf with hooks such that the MIPS architecture code can access the FP mode information & reject invalid FP modes. Patches 4-7 introduce support for operating with "hybrid FPRs" - a scheme in which odd single precision registers alias with the upper 32b of the preceeding even double as is typical with FR=0, but where all 32 64b doubles are also available. This is implemented by trapping & emulating single precision register accesses using a new Config5.FRE bit. Patches 8 & 9 introduce the .MIPS.abiflags section along with the kernel support for reading it & treating binaries accordingly. Patch 10 adds a simple debug option to test the implementation of hybrid FPRs by forcing all code that can operate in that mode to do so, which is usually avoided due to the overhead of trapping & emulating. Paul Burton (10): binfmt_elf: hoist ELF program header loading to a function binfmt_elf: load interpreter program headers earlier binfmt_elf: allow arch code to examine PT_LOPROC ... PT_HIPROC headers MIPS: define bits introduced for hybrid FPRs MIPS: detect presence of the FRE & UFR bits MIPS: ensure Config5.UFE is clear on boot MIPS: support for hybrid FPRs MIPS: ELF: add definition for the .MIPS.abiflags section MIPS: ELF: set FP mode according to .MIPS.abiflags MIPS: Kconfig option to better exercise/debug hybrid FPRs arch/mips/Kconfig | 1 + arch/mips/Kconfig.debug | 13 +++ arch/mips/include/asm/cpu-features.h | 4 + arch/mips/include/asm/cpu.h | 1 + arch/mips/include/asm/elf.h | 74 +++++++++++--- arch/mips/include/asm/fpu.h | 49 ++++++++-- arch/mips/include/asm/mipsregs.h | 3 + arch/mips/include/asm/thread_info.h | 2 + arch/mips/kernel/Makefile | 7 +- arch/mips/kernel/cpu-probe.c | 4 +- arch/mips/kernel/elf.c | 181 +++++++++++++++++++++++++++++++++++ arch/mips/kernel/traps.c | 47 +++++++++ arch/mips/math-emu/cp1emu.c | 9 +- fs/Kconfig.binfmt | 3 + fs/binfmt_elf.c | 169 ++++++++++++++++++++------------ include/linux/elf.h | 73 ++++++++++++++ 16 files changed, 549 insertions(+), 91 deletions(-) create mode 100644 arch/mips/kernel/elf.c -- 2.0.4
