[PATCH v3 4/8] x86: Use __pa_symbol instead of __pa on C visible symbols

Alexander Duyck
2012-11-05T19:05:26Z

When I made an attempt at separating __pa_symbol and __pa I found that there
were a number of cases where __pa was used on an obvious symbol.

I also caught one non-obvious case as _brk_start and _brk_end are based on the
address of __brk_base which is a C visible symbol.

In mark_rodata_ro I was able to reduce the overhead of kernel symbol to
virtual memory translation by using a combination of __va(__pa_symbol())
instead of page_address(virt_to_page()).

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
---

v3: Added changes to init_64.c function mark_rodata_ro to avoid unnecessary
conversion to and from a page when all that is wanted is a virtual
address.

arch/x86/kernel/cpu/intel.c | 2 +-
arch/x86/kernel/setup.c | 16 ++++++++--------
arch/x86/mm/init_64.c | 18 ++++++++----------
arch/x86/mm/pageattr.c | 8 ++++----
arch/x86/platform/efi/efi.c | 4 ++--
arch/x86/realmode/init.c | 8 ++++----
6 files changed, 27 insertions(+), 29 deletions(-)

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 198e019..2249e7e 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -168,7 +168,7 @@ int __cpuinit ppro_with_ram_bug(void)
#ifdef CONFIG_X86_F00F_BUG
static void __cpuinit trap_init_f00f_bug(void)
{
- __set_fixmap(FIX_F00F_IDT, __pa(&idt_table), PAGE_KERNEL_RO);
+ __set_fixmap(FIX_F00F_IDT, __pa_symbol(idt_table), PAGE_KERNEL_RO);

/*
* Update the IDT descriptor and reload the IDT so that
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index e800bc6..4343570 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -300,8 +300,8 @@ static void __init cleanup_highmap(void)
static void __init reserve_brk(void)
{
if (_brk_end > _brk_start)
- memblock_reserve(__pa(_brk_start),
- __pa(_brk_end) - __pa(_brk_start));
+ memblock_reserve(__pa_symbol(_brk_start),
+ _brk_end - _brk_start);

/* Mark brk area as locked down and no longer taking any
new allocations */
@@ -761,12 +761,12 @@ void __init setup_arch(char **cmdline_p)
init_mm.end_data = (unsigned long) _edata;
init_mm.brk = _brk_end;

- code_resource.start = virt_to_phys(_text);
- code_resource.end = virt_to_phys(_etext)-1;
- data_resource.start = virt_to_phys(_etext);
- data_resource.end = virt_to_phys(_edata)-1;
- bss_resource.start = virt_to_phys(&__bss_start);
- bss_resource.end = virt_to_phys(&__bss_stop)-1;
+ code_resource.start = __pa_symbol(_text);
+ code_resource.end = __pa_symbol(_etext)-1;
+ data_resource.start = __pa_symbol(_etext);
+ data_resource.end = __pa_symbol(_edata)-1;
+ bss_resource.start = __pa_symbol(__bss_start);
+ bss_resource.end = __pa_symbol(__bss_stop)-1;

#ifdef CONFIG_CMDLINE_BOOL
#ifdef CONFIG_CMDLINE_OVERRIDE
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 3baff25..0374a10 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -770,12 +770,10 @@ void set_kernel_text_ro(void)
void mark_rodata_ro(void)
{
unsigned long start = PFN_ALIGN(_text);
- unsigned long rodata_start =
- ((unsigned long)__start_rodata + PAGE_SIZE - 1) & PAGE_MASK;
+ unsigned long rodata_start = PFN_ALIGN(__start_rodata);
unsigned long end = (unsigned long) &__end_rodata_hpage_align;
- unsigned long text_end = PAGE_ALIGN((unsigned long) &__stop___ex_table);
- unsigned long rodata_end = PAGE_ALIGN((unsigned long) &__end_rodata);
- unsigned long data_start = (unsigned long) &_sdata;
+ unsigned long text_end = PFN_ALIGN(&__stop___ex_table);
+ unsigned long rodata_end = PFN_ALIGN(&__end_rodata);

printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
(end - start) >> 10);
@@ -800,12 +798,12 @@ void mark_rodata_ro(void)
#endif

free_init_pages("unused kernel memory",
- (unsigned long) page_address(virt_to_page(text_end)),
- (unsigned long)
- page_address(virt_to_page(rodata_start)));
+ (unsigned long) __va(__pa_symbol(text_end)),
+ (unsigned long) __va(__pa_symbol(rodata_start)));
+
free_init_pages("unused kernel memory",
- (unsigned long) page_address(virt_to_page(rodata_end)),
- (unsigned long) page_address(virt_to_page(data_start)));
+ (unsigned long) __va(__pa_symbol(rodata_end)),
+ (unsigned long) __va(__pa_symbol(_sdata)));
}

#endif
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index a718e0d..40f92f3 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -94,12 +94,12 @@ static inline void split_page_count(int level) { }

static inline unsigned long highmap_start_pfn(void)
{
- return __pa(_text) >> PAGE_SHIFT;
+ return __pa_symbol(_text) >> PAGE_SHIFT;
}

static inline unsigned long highmap_end_pfn(void)
{
- return __pa(roundup(_brk_end, PMD_SIZE)) >> PAGE_SHIFT;
+ return __pa_symbol(roundup(_brk_end, PMD_SIZE)) >> PAGE_SHIFT;
}

#endif
@@ -276,8 +276,8 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address,
* The .rodata section needs to be read-only. Using the pfn
* catches all aliases.
*/
- if (within(pfn, __pa((unsigned long)__start_rodata) >> PAGE_SHIFT,
- __pa((unsigned long)__end_rodata) >> PAGE_SHIFT))
+ if (within(pfn, __pa_symbol(__start_rodata) >> PAGE_SHIFT,
+ __pa_symbol(__end_rodata) >> PAGE_SHIFT))
pgprot_val(forbidden) |= _PAGE_RW;

#if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA)
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index ad44391..1b60026 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -410,8 +410,8 @@ void __init efi_reserve_boot_services(void)
* - Not within any part of the kernel
* - Not the bios reserved area
*/
- if ((start+size >= virt_to_phys(_text)
- && start <= virt_to_phys(_end)) ||
+ if ((start+size >= __pa_symbol(_text)
+ && start <= __pa_symbol(_end)) ||
!e820_all_mapped(start, start+size, E820_RAM) ||
memblock_is_region_reserved(start, size)) {
/* Could not reserve, skip it */
diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
index cbca565..8045026 100644
--- a/arch/x86/realmode/init.c
+++ b/arch/x86/realmode/init.c
@@ -62,9 +62,9 @@ void __init setup_real_mode(void)
__va(real_mode_header->trampoline_header);

#ifdef CONFIG_X86_32
- trampoline_header->start = __pa(startup_32_smp);
+ trampoline_header->start = __pa_symbol(startup_32_smp);
trampoline_header->gdt_limit = __BOOT_DS + 7;
- trampoline_header->gdt_base = __pa(boot_gdt);
+ trampoline_header->gdt_base = __pa_symbol(boot_gdt);
#else
/*
* Some AMD processors will #GP(0) if EFER.LMA is set in WRMSR
@@ -78,8 +78,8 @@ void __init setup_real_mode(void)
*trampoline_cr4_features = read_cr4();

trampoline_pgd = (u64 *) __va(real_mode_header->trampoline_pgd);
- trampoline_pgd[0] = __pa(level3_ident_pgt) + _KERNPG_TABLE;
- trampoline_pgd[511] = __pa(level3_kernel_pgt) + _KERNPG_TABLE;
+ trampoline_pgd[0] = __pa_symbol(level3_ident_pgt) + _KERNPG_TABLE;
+ trampoline_pgd[511] = __pa_symbol(level3_kernel_pgt) + _KERNPG_TABLE;
#endif
}