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* [PATCH v2 0/2] Fix binfmt_flat loader for RISC-V
@ 2021-04-07 15:49 Damien Le Moal
  2021-04-07 15:49 ` [PATCH v2 1/2] binfmt_flat: allow not offsetting data start Damien Le Moal
                   ` (2 more replies)
  0 siblings, 3 replies; 10+ messages in thread
From: Damien Le Moal @ 2021-04-07 15:49 UTC (permalink / raw)
  To: Palmer Dabbelt, linux-riscv, Alexander Viro, linux-kernel
  Cc: Max Filippov, Greg Ungerer, Anup Patel, Christoph Hellwig

RISC-V NOMMU flat binaries cannot tolerate a gap between the text and
data section as the toolchain fully resolves at compile time the PC
relative global pointer (__global_pointer$ value loaded in gp register).
Without a relocation entry provided, the flat bin loader cannot fix the
value if a gap is introduced and executables fail to run.

This series fixes this problem by allowing an architecture to request
the flat loader to suppress the gap between the text and data sections.
The first patch fixes binfmt_flat flat_load_file() using the new
configuration option CONFIG_BINFMT_FLAT_NO_TEXT_DATA_GAP. The second
patch enables this option for RISCV NOMMU builds.

These patches do not change the binfmt_flat loader behavior for other
architectures.

Changes from v1:
* Replace FLAT_TEXT_DATA_NO_GAP macro with
  CONFIG_BINFMT_FLAT_NO_TEXT_DATA_GAP config option (patch 1).
* Remove the addition of riscv/include/asm/flat.h and set
  CONFIG_BINFMT_FLAT_NO_TEXT_DATA_GAP for RISCV and !MMU

Damien Le Moal (2):
  binfmt_flat: allow not offsetting data start
  riscv: Disable text-data gap in flat binaries

 arch/riscv/Kconfig |  1 +
 fs/Kconfig.binfmt  |  3 +++
 fs/binfmt_flat.c   | 21 +++++++++++++++------
 3 files changed, 19 insertions(+), 6 deletions(-)

-- 
2.30.2


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^ permalink raw reply	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2021-04-16  7:47 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-04-07 15:49 [PATCH v2 0/2] Fix binfmt_flat loader for RISC-V Damien Le Moal
2021-04-07 15:49 ` [PATCH v2 1/2] binfmt_flat: allow not offsetting data start Damien Le Moal
2021-04-07 15:49 ` [PATCH v2 2/2] riscv: Disable text-data gap in flat binaries Damien Le Moal
2021-04-15  0:32 ` [PATCH v2 0/2] Fix binfmt_flat loader for RISC-V Damien Le Moal
2021-04-15  5:46   ` Palmer Dabbelt
2021-04-15  5:56     ` Christoph Hellwig
2021-04-15  6:16       ` Damien Le Moal
2021-04-16  0:21       ` Al Viro
2021-04-16  0:26         ` Damien Le Moal
2021-04-16  7:26           ` Greg Ungerer

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