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authorMichael Ellerman <mpe@ellerman.id.au>2017-10-09 21:54:05 +1100
committerMichael Ellerman <mpe@ellerman.id.au>2017-10-22 12:08:31 +0200
commit727f13616c45caa72e4325c5027c1a8f41e745a9 (patch)
tree081c0bfe2b0a848f8f798156693afc02d2972c64 /arch/powerpc/Kconfig.debug
parent5c2511bff47ba7fb09268ee8ebbf5237da5c0b84 (diff)
powerpc: Disable the fast-endian switch syscall by default
Back in 2008 we added support for "fast little-endian switch" in the syscall path. This added a special case syscall number 0x1ebe, which is caught very early in the system call exception and switches endian with as little overhead as possible. See commit 745a14cc264b ("[POWERPC] Add fast little-endian switch system call") for full details. Although it is fast, it's also completely non standard. The "syscall number" is out of the range of normal syscalls, it can't be traced or audited, and it's a bit of a wart. To the best of our knowledge it was only used by one program, now long since discontinued. So in an effort to shake out any current users, put it behind a config option, and make it default n. If anyone *is* using it they can quickly reinstate it with a rebuild, and we can flip it to default y. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/Kconfig.debug')
-rw-r--r--arch/powerpc/Kconfig.debug6
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug
index c86df246339e..b8a1eb42a38d 100644
--- a/arch/powerpc/Kconfig.debug
+++ b/arch/powerpc/Kconfig.debug
@@ -369,4 +369,10 @@ config PPC_HTDUMP
def_bool y
depends on PPC_PTDUMP && PPC_BOOK3S
+config PPC_FAST_ENDIAN_SWITCH
+ bool "Deprecated fast endian-switch syscall"
+ depends on DEBUG_KERNEL && PPC_BOOK3S_64
+ help
+ If you're unsure what this is, say N.
+
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