From 139ec7c416248b9ea227d21839235344edfee1e0 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Thu, 7 Dec 2006 02:14:08 +0100 Subject: [PATCH] paravirt: Patch inline replacements for paravirt intercepts It turns out that the most called ops, by several orders of magnitude, are the interrupt manipulation ops. These are obvious candidates for patching, so mark them up and create infrastructure for it. The method used is that the ops structure has a patch function, which is called for each place which needs to be patched: this returns a number of instructions (the rest are NOP-padded). Usually we can spare a register (%eax) for the binary patched code to use, but in a couple of critical places in entry.S we can't: we make the clobbers explicit at the call site, and manually clobber the allowed registers in debug mode as an extra check. And: Don't abuse CONFIG_DEBUG_KERNEL, add CONFIG_DEBUG_PARAVIRT. And: AK: Fix warnings in x86-64 alternative.c build And: AK: Fix compilation with defconfig And: ^From: Andrew Morton Some binutlises still like to emit references to __stop_parainstructions and __start_parainstructions. And: AK: Fix warnings about unused variables when PARAVIRT is disabled. Signed-off-by: Rusty Russell Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Chris Wright Signed-off-by: Zachary Amsden Signed-off-by: Andi Kleen Signed-off-by: Andrew Morton --- arch/i386/Kconfig.debug | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'arch/i386/Kconfig.debug') diff --git a/arch/i386/Kconfig.debug b/arch/i386/Kconfig.debug index b31c0802e1c..f68cc6f215f 100644 --- a/arch/i386/Kconfig.debug +++ b/arch/i386/Kconfig.debug @@ -85,4 +85,14 @@ config DOUBLEFAULT option saves about 4k and might cause you much additional grey hair. +config DEBUG_PARAVIRT + bool "Enable some paravirtualization debugging" + default y + depends on PARAVIRT && DEBUG_KERNEL + help + Currently deliberately clobbers regs which are allowed to be + clobbered in inlined paravirt hooks, even in native mode. + If turning this off solves a problem, then DISABLE_INTERRUPTS() or + ENABLE_INTERRUPTS() is lying about what registers can be clobbered. + endmenu -- cgit v1.2.3-70-g09d2