From b9af7c0d44b8bb71e3af5e94688d076414aa8c87 Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Wed, 14 Oct 2009 14:46:55 -0700 Subject: x86-64: preserve large page mapping for 1st 2MB kernel txt with CONFIG_DEBUG_RODATA In the first 2MB, kernel text is co-located with kernel static page tables setup by head_64.S. CONFIG_DEBUG_RODATA chops this 2MB large page mapping to small 4KB pages as we mark the kernel text as RO, leaving the static page tables as RW. With CONFIG_DEBUG_RODATA disabled, OLTP run on NHM-EP shows 1% improvement with 2% reduction in system time and 1% improvement in iowait idle time. To recover this, move the kernel static page tables to .data section, so that we don't have to break the first 2MB of kernel text to small pages with CONFIG_DEBUG_RODATA. Signed-off-by: Suresh Siddha LKML-Reference: <20091014220254.063193621@sbs-t61.sc.intel.com> Signed-off-by: H. Peter Anvin --- arch/x86/kernel/head_64.S | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/x86/kernel/head_64.S') diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 780cd928fcd5..b55ee4ff509f 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -262,11 +262,11 @@ ENTRY(secondary_startup_64) .quad x86_64_start_kernel ENTRY(initial_gs) .quad INIT_PER_CPU_VAR(irq_stack_union) - __FINITDATA ENTRY(stack_start) .quad init_thread_union+THREAD_SIZE-8 .word 0 + __FINITDATA bad_address: jmp bad_address @@ -340,6 +340,7 @@ ENTRY(name) i = i + 1 ; \ .endr + .data /* * This default setting generates an ident mapping at address 0x100000 * and a mapping for the kernel that precisely maps virtual address -- cgit v1.2.2 From 8ec6993d9f7d961014af970ded57542961fe9ad9 Mon Sep 17 00:00:00 2001 From: Brian Gerst Date: Wed, 25 Nov 2009 11:17:36 -0500 Subject: x86, 64-bit: Set data segments to null after switching to 64-bit mode This prevents kernel threads from inheriting non-null segment selectors, and causing optimizations in __switch_to() to be ineffective. Signed-off-by: Brian Gerst Cc: Tim Blechmann Cc: Linus Torvalds Cc: H. Peter Anvin Cc: Jeremy Fitzhardinge Cc: Jan Beulich LKML-Reference: <1259165856-3512-1-git-send-email-brgerst@gmail.com> Signed-off-by: Ingo Molnar --- arch/x86/kernel/head_64.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/x86/kernel/head_64.S') diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 26406601031c..17ba9ecf27c5 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -212,8 +212,8 @@ ENTRY(secondary_startup_64) */ lgdt early_gdt_descr(%rip) - /* set up data segments. actually 0 would do too */ - movl $__KERNEL_DS,%eax + /* set up data segments */ + xorl %eax,%eax movl %eax,%ds movl %eax,%ss movl %eax,%es -- cgit v1.2.2 From 3ad2f3fbb961429d2aa627465ae4829758bc7e07 Mon Sep 17 00:00:00 2001 From: Daniel Mack Date: Wed, 3 Feb 2010 08:01:28 +0800 Subject: tree-wide: Assorted spelling fixes In particular, several occurances of funny versions of 'success', 'unknown', 'therefore', 'acknowledge', 'argument', 'achieve', 'address', 'beginning', 'desirable', 'separate' and 'necessary' are fixed. Signed-off-by: Daniel Mack Cc: Joe Perches Cc: Junio C Hamano Signed-off-by: Jiri Kosina --- arch/x86/kernel/head_64.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/kernel/head_64.S') diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 2d8b5035371c..3d1e6f16b7a6 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -27,7 +27,7 @@ #define GET_CR2_INTO_RCX movq %cr2, %rcx #endif -/* we are not able to switch in one step to the final KERNEL ADRESS SPACE +/* we are not able to switch in one step to the final KERNEL ADDRESS SPACE * because we need identity-mapped pages. * */ -- cgit v1.2.2