[PATCH v2][EFI] Run EFI in physical mode

From: Takao Indoh
Date: Mon Aug 16 2010 - 19:09:33 EST

Hi all,

Thanks for many comments. I just changed some variables according to
Huang's comment.

On Mon, 16 Aug 2010 09:43:56 +0800, huang ying wrote:
>efi_flags and save_cr3 should be per-CPU, because they now will be
>used after SMP is enabled.

Ok, what I should do next is:

- x86 support
As I wrote, I don't have x86 machine where EFI works. Any
volunteer?
- ia64 support
I'm not sure we should do this, but I'll try if we need.
- Using common page tables instead of EFI own page table
Now I'm checking the thread below...
http://marc.info/?i=1280940316-7966-1-git-send-email-bp@xxxxxxxxx


Signed-off-by: Takao Indoh <indou.takao@xxxxxxxxxxxxxx>
---
arch/x86/include/asm/efi.h | 3
arch/x86/kernel/efi.c | 142 ++++++++++++++++++++++++++++++++++-
arch/x86/kernel/efi_32.c | 4
arch/x86/kernel/efi_64.c | 96 ++++++++++++++++++++++-
include/linux/efi.h | 1
include/linux/init.h | 1
init/main.c | 16 +++
7 files changed, 256 insertions(+), 7 deletions(-)

diff -Nurp linux-2.6.35.org/arch/x86/include/asm/efi.h linux-2.6.35/arch/x86/include/asm/efi.h
--- linux-2.6.35.org/arch/x86/include/asm/efi.h 2010-08-16 17:45:06.547622377 -0400
+++ linux-2.6.35/arch/x86/include/asm/efi.h 2010-08-16 17:45:39.021626213 -0400
@@ -93,6 +93,9 @@ extern int add_efi_memmap;
extern void efi_reserve_early(void);
extern void efi_call_phys_prelog(void);
extern void efi_call_phys_epilog(void);
+extern void efi_call_phys_prelog_in_physmode(void);
+extern void efi_call_phys_epilog_in_physmode(void);
+extern void efi_pagetable_init(void);

#ifndef CONFIG_EFI
/*
diff -Nurp linux-2.6.35.org/arch/x86/kernel/efi.c linux-2.6.35/arch/x86/kernel/efi.c
--- linux-2.6.35.org/arch/x86/kernel/efi.c 2010-08-16 17:45:06.500622377 -0400
+++ linux-2.6.35/arch/x86/kernel/efi.c 2010-08-16 17:45:39.022633025 -0400
@@ -57,6 +57,7 @@ struct efi_memory_map memmap;

static struct efi efi_phys __initdata;
static efi_system_table_t efi_systab __initdata;
+static efi_runtime_services_t phys_runtime;

static int __init setup_noefi(char *arg)
{
@@ -171,7 +172,7 @@ static efi_status_t __init phys_efi_set_
return status;
}

-static efi_status_t __init phys_efi_get_time(efi_time_t *tm,
+static efi_status_t __init phys_efi_get_time_early(efi_time_t *tm,
efi_time_cap_t *tc)
{
efi_status_t status;
@@ -182,6 +183,112 @@ static efi_status_t __init phys_efi_get_
return status;
}

+static efi_status_t phys_efi_get_time(efi_time_t *tm,
+ efi_time_cap_t *tc)
+{
+ efi_status_t status;
+
+ efi_call_phys_prelog_in_physmode();
+ status = efi_call_phys2((void*)phys_runtime.get_time, tm, tc);
+ efi_call_phys_epilog_in_physmode();
+ return status;
+}
+
+static efi_status_t __init phys_efi_set_time(efi_time_t *tm)
+{
+ efi_status_t status;
+
+ efi_call_phys_prelog_in_physmode();
+ status = efi_call_phys1((void*)phys_runtime.set_time, tm);
+ efi_call_phys_epilog_in_physmode();
+ return status;
+}
+
+static efi_status_t phys_efi_get_wakeup_time(efi_bool_t *enabled,
+ efi_bool_t *pending,
+ efi_time_t *tm)
+{
+ efi_status_t status;
+
+ efi_call_phys_prelog_in_physmode();
+ status = efi_call_phys3((void*)phys_runtime.get_wakeup_time, enabled,
+ pending, tm);
+ efi_call_phys_epilog_in_physmode();
+ return status;
+}
+
+static efi_status_t phys_efi_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm)
+{
+ efi_status_t status;
+ efi_call_phys_prelog_in_physmode();
+ status = efi_call_phys2((void*)phys_runtime.set_wakeup_time, enabled,
+ tm);
+ efi_call_phys_epilog_in_physmode();
+ return status;
+}
+
+static efi_status_t phys_efi_get_variable(efi_char16_t *name,
+ efi_guid_t *vendor,
+ u32 *attr,
+ unsigned long *data_size,
+ void *data)
+{
+ efi_status_t status;
+ efi_call_phys_prelog_in_physmode();
+ status = efi_call_phys5((void*)phys_runtime.get_variable, name, vendor,
+ attr, data_size, data);
+ efi_call_phys_epilog_in_physmode();
+ return status;
+}
+
+static efi_status_t phys_efi_get_next_variable(unsigned long *name_size,
+ efi_char16_t *name,
+ efi_guid_t *vendor)
+{
+ efi_status_t status;
+
+ efi_call_phys_prelog_in_physmode();
+ status = efi_call_phys3((void*)phys_runtime.get_next_variable,
+ name_size, name, vendor);
+ efi_call_phys_epilog_in_physmode();
+ return status;
+}
+
+static efi_status_t phys_efi_set_variable(efi_char16_t *name,
+ efi_guid_t *vendor,
+ unsigned long attr,
+ unsigned long data_size,
+ void *data)
+{
+ efi_status_t status;
+ efi_call_phys_prelog_in_physmode();
+ status = efi_call_phys5((void*)phys_runtime.set_variable, name,
+ vendor, attr, data_size, data);
+ efi_call_phys_epilog_in_physmode();
+ return status;
+}
+
+static efi_status_t phys_efi_get_next_high_mono_count(u32 *count)
+{
+ efi_status_t status;
+ efi_call_phys_prelog_in_physmode();
+ status = efi_call_phys1((void*)phys_runtime.get_next_high_mono_count,
+ count);
+ efi_call_phys_epilog_in_physmode();
+ return status;
+}
+
+static void phys_efi_reset_system(int reset_type,
+ efi_status_t status,
+ unsigned long data_size,
+ efi_char16_t *data)
+{
+ efi_call_phys_prelog_in_physmode();
+ efi_call_phys4((void*)phys_runtime.reset_system, reset_type, status,
+ data_size, data);
+ efi_call_phys_epilog_in_physmode();
+}
+
int efi_set_rtc_mmss(unsigned long nowtime)
{
int real_seconds, real_minutes;
@@ -434,7 +541,9 @@ void __init efi_init(void)
* Make efi_get_time can be called before entering
* virtual mode.
*/
- efi.get_time = phys_efi_get_time;
+ efi.get_time = phys_efi_get_time_early;
+
+ memcpy(&phys_runtime, runtime, sizeof(efi_runtime_services_t));
} else
printk(KERN_ERR "Could not map the EFI runtime service "
"table!\n");
@@ -465,6 +574,14 @@ void __init efi_init(void)
#if EFI_DEBUG
print_efi_memmap();
#endif
+
+#ifndef CONFIG_X86_64
+ /*
+ * Only x86_64 supports physical mode as of now. Use virtual mode
+ * forcibly.
+ */
+ usevirtefi = 1;
+#endif
}

static void __init runtime_code_page_mkexec(void)
@@ -578,6 +695,27 @@ void __init efi_enter_virtual_mode(void)
memmap.map = NULL;
}

+void __init efi_setup_physical_mode(void)
+{
+#ifdef CONFIG_X86_64
+ efi_pagetable_init();
+#endif
+ efi.get_time = phys_efi_get_time;
+ efi.set_time = phys_efi_set_time;
+ efi.get_wakeup_time = phys_efi_get_wakeup_time;
+ efi.set_wakeup_time = phys_efi_set_wakeup_time;
+ efi.get_variable = phys_efi_get_variable;
+ efi.get_next_variable = phys_efi_get_next_variable;
+ efi.set_variable = phys_efi_set_variable;
+ efi.get_next_high_mono_count =
+ phys_efi_get_next_high_mono_count;
+ efi.reset_system = phys_efi_reset_system;
+ efi.set_virtual_address_map = NULL; /* Not needed */
+
+ early_iounmap(memmap.map, memmap.nr_map * memmap.desc_size);
+ memmap.map = NULL;
+}
+
/*
* Convenience functions to obtain memory types and attributes
*/
diff -Nurp linux-2.6.35.org/arch/x86/kernel/efi_32.c linux-2.6.35/arch/x86/kernel/efi_32.c
--- linux-2.6.35.org/arch/x86/kernel/efi_32.c 2010-08-16 17:45:06.522621888 -0400
+++ linux-2.6.35/arch/x86/kernel/efi_32.c 2010-08-16 17:45:39.022633025 -0400
@@ -110,3 +110,7 @@ void efi_call_phys_epilog(void)

local_irq_restore(efi_rt_eflags);
}
+
+void efi_call_phys_prelog_in_physmode(void) { /* Not supported */ }
+void efi_call_phys_epilog_in_physmode(void) { /* Not supported */ }
+
diff -Nurp linux-2.6.35.org/arch/x86/kernel/efi_64.c linux-2.6.35/arch/x86/kernel/efi_64.c
--- linux-2.6.35.org/arch/x86/kernel/efi_64.c 2010-08-16 17:45:06.499622447 -0400
+++ linux-2.6.35/arch/x86/kernel/efi_64.c 2010-08-16 17:45:39.023650384 -0400
@@ -39,7 +39,9 @@
#include <asm/fixmap.h>

static pgd_t save_pgd __initdata;
-static unsigned long efi_flags __initdata;
+static DEFINE_PER_CPU(unsigned long, efi_flags);
+static DEFINE_PER_CPU(unsigned long, save_cr3);
+static pgd_t efi_pgd[PTRS_PER_PGD] __page_aligned_bss;

static void __init early_mapping_set_exec(unsigned long start,
unsigned long end,
@@ -80,7 +82,7 @@ void __init efi_call_phys_prelog(void)
unsigned long vaddress;

early_runtime_code_mapping_set_exec(1);
- local_irq_save(efi_flags);
+ local_irq_save(get_cpu_var(efi_flags));
vaddress = (unsigned long)__va(0x0UL);
save_pgd = *pgd_offset_k(0x0UL);
set_pgd(pgd_offset_k(0x0UL), *pgd_offset_k(vaddress));
@@ -94,10 +96,23 @@ void __init efi_call_phys_epilog(void)
*/
set_pgd(pgd_offset_k(0x0UL), save_pgd);
__flush_tlb_all();
- local_irq_restore(efi_flags);
+ local_irq_restore(get_cpu_var(efi_flags));
early_runtime_code_mapping_set_exec(0);
}

+void efi_call_phys_prelog_in_physmode(void)
+{
+ local_irq_save(get_cpu_var(efi_flags));
+ get_cpu_var(save_cr3)= read_cr3();
+ write_cr3(virt_to_phys(efi_pgd));
+}
+
+void efi_call_phys_epilog_in_physmode(void)
+{
+ write_cr3(get_cpu_var(save_cr3));
+ local_irq_restore(get_cpu_var(efi_flags));
+}
+
void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
u32 type)
{
@@ -112,3 +127,78 @@ void __iomem *__init efi_ioremap(unsigne

return (void __iomem *)__va(phys_addr);
}
+
+static pud_t *fill_pud(pgd_t *pgd, unsigned long vaddr)
+{
+ if (pgd_none(*pgd)) {
+ pud_t *pud = (pud_t *)get_zeroed_page(GFP_ATOMIC);
+ set_pgd(pgd, __pgd(_PAGE_TABLE | __pa(pud)));
+ if (pud != pud_offset(pgd, 0))
+ printk(KERN_ERR "EFI PAGETABLE BUG #00! %p <-> %p\n",
+ pud, pud_offset(pgd, 0));
+ }
+ return pud_offset(pgd, vaddr);
+}
+
+static pmd_t *fill_pmd(pud_t *pud, unsigned long vaddr)
+{
+ if (pud_none(*pud)) {
+ pmd_t *pmd = (pmd_t *)get_zeroed_page(GFP_ATOMIC);
+ set_pud(pud, __pud(_PAGE_TABLE | __pa(pmd)));
+ if (pmd != pmd_offset(pud, 0))
+ printk(KERN_ERR "EFI PAGETABLE BUG #01! %p <-> %p\n",
+ pmd, pmd_offset(pud, 0));
+ }
+ return pmd_offset(pud, vaddr);
+}
+
+static pte_t *fill_pte(pmd_t *pmd, unsigned long vaddr)
+{
+ if (pmd_none(*pmd)) {
+ pte_t *pte = (pte_t *)get_zeroed_page(GFP_ATOMIC);
+ set_pmd(pmd, __pmd(_PAGE_TABLE | __pa(pte)));
+ if (pte != pte_offset_kernel(pmd, 0))
+ printk(KERN_ERR "EFI PAGETABLE BUG #02!\n");
+ }
+ return pte_offset_kernel(pmd, vaddr);
+}
+
+void __init efi_pagetable_init(void)
+{
+ efi_memory_desc_t *md;
+ unsigned long size;
+ u64 start_pfn, end_pfn, pfn, vaddr;
+ void *p;
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte;
+
+ memset(efi_pgd, 0, sizeof(efi_pgd));
+ for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
+ md = p;
+ if (!(md->type & EFI_RUNTIME_SERVICES_CODE) &&
+ !(md->type & EFI_RUNTIME_SERVICES_DATA))
+ continue;
+
+ start_pfn = md->phys_addr >> PAGE_SHIFT;
+ size = md->num_pages << EFI_PAGE_SHIFT;
+ end_pfn = PFN_UP(md->phys_addr + size);
+
+ for (pfn = start_pfn; pfn <= end_pfn; pfn++) {
+ vaddr = pfn << PAGE_SHIFT;
+ pgd = efi_pgd + pgd_index(vaddr);
+ pud = fill_pud(pgd, vaddr);
+ pmd = fill_pmd(pud, vaddr);
+ pte = fill_pte(pmd, vaddr);
+ if (md->type & EFI_RUNTIME_SERVICES_CODE)
+ set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
+ else
+ set_pte(pte, pfn_pte(pfn, PAGE_KERNEL));
+ }
+ }
+ pgd = efi_pgd + pgd_index(PAGE_OFFSET);
+ set_pgd(pgd, *pgd_offset_k(PAGE_OFFSET));
+ pgd = efi_pgd + pgd_index(__START_KERNEL_map);
+ set_pgd(pgd, *pgd_offset_k(__START_KERNEL_map));
+}
diff -Nurp linux-2.6.35.org/include/linux/efi.h linux-2.6.35/include/linux/efi.h
--- linux-2.6.35.org/include/linux/efi.h 2010-08-16 17:45:06.015622308 -0400
+++ linux-2.6.35/include/linux/efi.h 2010-08-16 17:45:39.023650384 -0400
@@ -290,6 +290,7 @@ extern void efi_map_pal_code (void);
extern void efi_memmap_walk (efi_freemem_callback_t callback, void *arg);
extern void efi_gettimeofday (struct timespec *ts);
extern void efi_enter_virtual_mode (void); /* switch EFI to virtual mode, if possible */
+extern void efi_setup_physical_mode(void);
extern u64 efi_get_iobase (void);
extern u32 efi_mem_type (unsigned long phys_addr);
extern u64 efi_mem_attributes (unsigned long phys_addr);
diff -Nurp linux-2.6.35.org/include/linux/init.h linux-2.6.35/include/linux/init.h
--- linux-2.6.35.org/include/linux/init.h 2010-08-16 17:45:06.059622448 -0400
+++ linux-2.6.35/include/linux/init.h 2010-08-16 17:45:39.024651054 -0400
@@ -142,6 +142,7 @@ extern int do_one_initcall(initcall_t fn
extern char __initdata boot_command_line[];
extern char *saved_command_line;
extern unsigned int reset_devices;
+extern unsigned int usevirtefi;

/* used by init/main.c */
void setup_arch(char **);
diff -Nurp linux-2.6.35.org/init/main.c linux-2.6.35/init/main.c
--- linux-2.6.35.org/init/main.c 2010-08-16 17:45:05.729683838 -0400
+++ linux-2.6.35/init/main.c 2010-08-16 17:45:39.025650051 -0400
@@ -200,6 +200,14 @@ static int __init set_reset_devices(char

__setup("reset_devices", set_reset_devices);

+unsigned int usevirtefi;
+static int __init set_virt_efi(char *str)
+{
+ usevirtefi = 1;
+ return 1;
+}
+__setup("virtefi", set_virt_efi);
+
static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
static const char *panic_later, *panic_param;
@@ -676,8 +684,12 @@ asmlinkage void __init start_kernel(void
pidmap_init();
anon_vma_init();
#ifdef CONFIG_X86
- if (efi_enabled)
- efi_enter_virtual_mode();
+ if (efi_enabled) {
+ if (usevirtefi)
+ efi_enter_virtual_mode();
+ else
+ efi_setup_physical_mode();
+ }
#endif
thread_info_cache_init();
cred_init();

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