x86/entry: Reduce the code footprint of the 'idtentry' macro
authorDominik Brodowski <linux@dominikbrodowski.net>
Wed, 14 Feb 2018 17:59:23 +0000 (18:59 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 15 Mar 2018 09:54:36 +0000 (10:54 +0100)
commitb690fda31a4701d7ee847aa495f8fc7fb3927abc
treee714d249f1d4dff660e86a664dfda494b80021a6
parent2e19277e1df539cf94b435042fbad9bdb7775ab6
x86/entry: Reduce the code footprint of the 'idtentry' macro

commit 9e809d15d6b692fa061d74be7aaab1c79f6784b8 upstream.

Play a little trick in the generic PUSH_AND_CLEAR_REGS macro
to insert the GP registers "above" the original return address.

This allows us to (re-)insert the macro in error_entry() and
paranoid_entry() and to remove it from the idtentry macro. This
reduces the static footprint significantly:

   text    data     bss     dec     hex filename
  24307       0       0   24307    5ef3 entry_64.o-orig
  20987       0       0   20987    51fb entry_64.o

Co-developed-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180214175924.23065-2-linux@dominikbrodowski.net
[ Small tweaks to comments. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/x86/entry/calling.h
arch/x86/entry/entry_64.S