[PATCH 2/2] powerpc/64: Increase stack redzone for 64-bit kernel to 512 bytes

Segher Boessenkool segher at kernel.crashing.org
Mon Oct 1 19:07:19 AEST 2018


On Sat, Sep 29, 2018 at 11:25:20PM -0700, Bin Meng wrote:
>  /*
> - * Size of redzone that userspace is allowed to use below the stack
> + * Size of redzone that kernel/userspace is allowed to use below the stack
>   * pointer.  This is 288 in the 64-bit big-endian ELF ABI, and 512 in
>   * the new ELFv2 little-endian ABI, so we allow the larger amount.
> - *
> - * For kernel code we allow a 288-byte redzone, in order to conserve
> - * kernel stack space; gcc currently only uses 288 bytes, and will
> - * hopefully allow explicit control of the redzone size in future.
>   */

Btw: patches welcome!  This will never be useful for userland code, so no
one in GCC land is looking at this (we did not even know it is wanted).


Segher


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