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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 18/18] x86: add multiboot2 protocol support for EFI platforms
On 30/01/15 17:54, Daniel Kiper wrote:
> Signed-off-by: Daniel Kiper <daniel.kiper@xxxxxxxxxx>
> ---
> xen/arch/x86/boot/head.S | 174
> +++++++++++++++++++++++++++++++++++--
> xen/arch/x86/efi/efi-boot.h | 29 +++++++
> xen/arch/x86/setup.c | 23 ++---
> xen/arch/x86/x86_64/asm-offsets.c | 2 +
> xen/common/efi/boot.c | 11 +++
> 5 files changed, 222 insertions(+), 17 deletions(-)
>
> diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
> index 7861057..89f5aa7 100644
> --- a/xen/arch/x86/boot/head.S
> +++ b/xen/arch/x86/boot/head.S
> @@ -8,6 +8,7 @@
> #include <asm/page.h>
> #include <asm/msr.h>
> #include <asm/cpufeature.h>
> +#include <asm/processor.h>
>
> .text
> .code32
> @@ -57,6 +58,9 @@ ENTRY(start)
> .long .Lmultiboot2_info_req_end - .Lmultiboot2_info_req
> .long MULTIBOOT2_TAG_TYPE_BASIC_MEMINFO
> .long MULTIBOOT2_TAG_TYPE_MMAP
> + .long MULTIBOOT2_TAG_TYPE_EFI_BS
> + .long MULTIBOOT2_TAG_TYPE_EFI64
> + .long MULTIBOOT2_TAG_TYPE_EFI64_IH
> .Lmultiboot2_info_req_end:
>
> .align MULTIBOOT2_TAG_ALIGN
> @@ -80,6 +84,19 @@ ENTRY(start)
> .long 0 /* Number of the lines - no preference. */
> .long 0 /* Number of bits per pixel - no preference. */
>
> + /* Do not disable EFI boot services. */
> + .align MULTIBOOT2_TAG_ALIGN
> + .short MULTIBOOT2_HEADER_TAG_EFI_BS
> + .short MULTIBOOT2_HEADER_TAG_OPTIONAL
> + .long 8 /* Tag size. */
> +
> + /* EFI64 entry point. */
> + .align MULTIBOOT2_TAG_ALIGN
> + .short MULTIBOOT2_HEADER_TAG_ENTRY_ADDRESS_EFI64
> + .short MULTIBOOT2_HEADER_TAG_OPTIONAL
> + .long 12 /* Tag size. */
> + .long sym_phys(__efi64_start)
> +
> /* Multiboot2 header end tag. */
> .align MULTIBOOT2_TAG_ALIGN
> .short MULTIBOOT2_HEADER_TAG_END
> @@ -94,6 +111,17 @@ ENTRY(start)
> gdt_boot_descr:
> .word 6*8-1
> .long sym_phys(trampoline_gdt)
> + .long 0 /* Needed for 64-bit lgdt */
> +
> +cs32_switch_addr:
> + .long sym_phys(cs32_switch)
> + .long BOOT_CS32
.word
ljmpl refers to an m32:16 not an m32:32
> +
> +efi_st:
> + .quad 0
> +
> +efi_ih:
> + .quad 0
>
> .Lbad_cpu_msg: .asciz "ERR: Not a 64-bit CPU!"
> .Lbad_ldr_msg: .asciz "ERR: Not a Multiboot bootloader!"
> @@ -124,6 +152,133 @@ print_err:
> .Lhalt: hlt
> jmp .Lhalt
>
> + .code64
> +
> +__efi64_start:
> + cld
> +
> + /* Bootloaders may set multiboot[12].mem_lower to a nonzero value */
> + xor %edx,%edx
> +
> + /* Check for Multiboot2 bootloader */
> + cmp $MULTIBOOT2_BOOTLOADER_MAGIC,%eax
> + je efi_multiboot2_proto
> +
> + jmp not_multiboot
not_multiboot is 32bit code. You must drop out of 64bit before using
it, or make a 64bit variant.
> +
> +efi_multiboot2_proto:
> + /* Skip Multiboot2 information fixed part */
> + lea MB2_fixed_sizeof(%ebx),%ecx
> +
> +0:
> + /* Get mem_lower from Multiboot2 information */
> + cmpl $MULTIBOOT2_TAG_TYPE_BASIC_MEMINFO,(%ecx)
> + jne 1f
> +
> + mov MB2_mem_lower(%ecx),%edx
> + jmp 4f
> +
> +1:
> + /* Get EFI SystemTable address from Multiboot2 information */
> + cmpl $MULTIBOOT2_TAG_TYPE_EFI64,(%ecx)
> + jne 2f
> +
> + lea MB2_efi64_st(%ecx),%esi
> + lea efi_st(%rip),%edi
> + movsq
This is complete overkill for copying a 64bit variable out of the tag
and into a local variable. Just use a plain 64bit load and store.
> +
> + /* Do not go into real mode on EFI platform */
> + movb $1,skip_realmode(%rip)
> +
> + jmp 4f
> +
> +2:
> + /* Get EFI ImageHandle address from Multiboot2 information */
> + cmpl $MULTIBOOT2_TAG_TYPE_EFI64_IH,(%ecx)
> + jne 3f
> +
> + lea MB2_efi64_ih(%ecx),%esi
> + lea efi_ih(%rip),%edi
> + movsq
And here.
> + jmp 4f
> +
> +3:
> + /* Is it the end of Multiboot2 information? */
> + cmpl $MULTIBOOT2_TAG_TYPE_END,(%ecx)
> + je run_bs
> +
> +4:
> + /* Go to next Multiboot2 information tag */
> + add MB2_tag_size(%ecx),%ecx
> + add $(MULTIBOOT2_TAG_ALIGN-1),%ecx
> + and $~(MULTIBOOT2_TAG_ALIGN-1),%ecx
> + jmp 0b
> +
> +run_bs:
> + push %rax
> + push %rdx
Does the EFI spec guarantee that we have a good stack to use at this point?
> +
> + /* Initialize BSS (no nasty surprises!) */
> + lea __bss_start(%rip),%rdi
> + lea _end(%rip),%rcx
> + sub %rdi,%rcx
> + xor %rax,%rax
xor %eax,%eax is shorter.
> + rep stosb
It would be more efficient to make sure that the linker aligns
__bss_start and _end on 8 byte boundaries, and use stosq instead.
> +
> + mov efi_ih(%rip),%rdi /* EFI ImageHandle */
> + mov efi_st(%rip),%rsi /* EFI SystemTable */
> + call efi_multiboot2
> +
> + pop %rcx
> + pop %rax
> +
> + shl $10-4,%rcx /* Convert multiboot2.mem_lower to
> bytes/16 */
> +
> + cli
This looks suspiciously out of place. Surely the EFI spec doesn't
permit entry with interrupts enabled?
> +
> + /* Initialise GDT */
> + lgdt gdt_boot_descr(%rip)
> +
> + /* Reload code selector */
> + ljmpl *cs32_switch_addr(%rip)
> +
> + .code32
> +
> +cs32_switch:
> + /* Initialise basic data segments */
> + mov $BOOT_DS,%edx
> + mov %edx,%ds
> + mov %edx,%es
> + mov %edx,%fs
> + mov %edx,%gs
> + mov %edx,%ss
> +
> + mov $sym_phys(cpu0_stack)+1024,%esp
> +
> + /* Disable paging */
> + mov %cr0,%edx
> + and $(~X86_CR0_PG),%edx
> + mov %edx,%cr0
> +
> + push %eax
> + push %ecx
> +
> + /* Disable Long Mode */
> + mov $MSR_EFER,%ecx
> + rdmsr
> + and $(~EFER_LME),%eax
> + wrmsr
> +
> + pop %ecx
> + pop %eax
> +
> + /* Turn off PAE */
> + mov %cr4,%edx
> + and $(~X86_CR4_PAE),%edx
> + mov %edx,%cr4
> +
> + jmp trampoline_setup
> +
> __start:
> cld
> cli
> @@ -151,10 +306,10 @@ __start:
> multiboot1_proto:
> /* Get mem_lower from Multiboot information */
> testb $MBI_MEMLIMITS,(%ebx)
> - jz trampoline_setup /* not available? BDA value will be fine
> */
> + jz bios_platform /* not available? BDA value will be fine
> */
>
> mov MB_mem_lower(%ebx),%edx
> - jmp trampoline_setup
> + jmp bios_platform
>
> multiboot2_proto:
> /* Skip Multiboot2 information fixed part */
> @@ -166,12 +321,12 @@ multiboot2_proto:
> jne 1f
>
> mov MB2_mem_lower(%ecx),%edx
> - jmp trampoline_setup
> + jmp bios_platform
>
> 1:
> /* Is it the end of Multiboot2 information? */
> cmpl $MULTIBOOT2_TAG_TYPE_END,(%ecx)
> - je trampoline_setup
> + je bios_platform
>
> /* Go to next Multiboot2 information tag */
> add MB2_tag_size(%ecx),%ecx
> @@ -179,7 +334,7 @@ multiboot2_proto:
> and $~(MULTIBOOT2_TAG_ALIGN-1),%ecx
> jmp 0b
>
> -trampoline_setup:
> +bios_platform:
> /* Set up trampoline segment 64k below EBDA */
> movzwl 0x40e,%ecx /* EBDA segment */
> cmp $0xa000,%ecx /* sanity check (high) */
> @@ -195,12 +350,13 @@ trampoline_setup:
> * multiboot structure (if available) and use the smallest.
> */
> cmp $0x100,%edx /* is the multiboot value too small? */
> - jb 2f /* if so, do not use it */
> + jb trampoline_setup /* if so, do not use it */
> shl $10-4,%edx
> cmp %ecx,%edx /* compare with BDA value */
> cmovb %edx,%ecx /* and use the smaller */
>
> -2: /* Reserve 64kb for the trampoline */
> +trampoline_setup:
> + /* Reserve 64kb for the trampoline */
> sub $0x1000,%ecx
>
> /* From arch/x86/smpboot.c: start_eip had better be page-aligned! */
> @@ -215,6 +371,9 @@ trampoline_setup:
> call reloc /* %ecx contains trampoline address */
> mov %eax,sym_phys(multiboot_ptr)
>
> + cmpb $1,sym_phys(skip_realmode)
> + je 1f
> +
> /* Initialize BSS (no nasty surprises!) */
> mov $sym_phys(__bss_start),%edi
> mov $sym_phys(_end),%ecx
> @@ -222,6 +381,7 @@ trampoline_setup:
> xor %eax,%eax
> rep stosb
>
> +1:
> /* Interrogate CPU extended features via CPUID. */
> mov $0x80000000,%eax
> cpuid
> diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
> index 6e98bc8..f50c10a 100644
> --- a/xen/arch/x86/efi/efi-boot.h
> +++ b/xen/arch/x86/efi/efi-boot.h
> @@ -223,6 +223,9 @@ static void *__init efi_arch_allocate_mmap_buffer(UINTN
> *map_size)
>
> static void __init efi_arch_pre_exit_boot(void)
> {
> + if ( !efi_loader )
> + return;
> +
> if ( !trampoline_phys )
> {
> if ( !cfg.addr )
> @@ -650,6 +653,32 @@ static bool_t __init
> efi_arch_use_config_file(EFI_SYSTEM_TABLE *SystemTable)
> return 1; /* x86 always uses a config file */
> }
>
> +void __init efi_multiboot2(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE
> *SystemTable)
> +{
> + EFI_GRAPHICS_OUTPUT_PROTOCOL *gop;
> + UINTN cols, gop_mode = ~0, rows;
> +
> + efi_platform = 1;
> + efi_loader = 0;
> +
> + efi_init(ImageHandle, SystemTable);
> +
> + efi_console_set_mode();
> +
> + if ( StdOut->QueryMode(StdOut, StdOut->Mode->Mode,
> + &cols, &rows) == EFI_SUCCESS )
> + efi_arch_console_init(cols, rows);
> +
> + gop = efi_get_gop();
> + gop_mode = efi_find_gop_mode(gop, 0, 0, 0);
> + efi_arch_edd();
> + efi_tables();
> + setup_efi_pci();
> + efi_variables();
> + efi_set_gop_mode(gop, gop_mode);
> + efi_exit_boot(ImageHandle, SystemTable);
> +}
> +
> /*
> * Local variables:
> * mode: C
> diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
> index aebd010..8991b12 100644
> --- a/xen/arch/x86/setup.c
> +++ b/xen/arch/x86/setup.c
> @@ -663,20 +663,23 @@ void __init noreturn __start_xen(unsigned long mbi_p)
> if ( ((unsigned long)cpu0_stack & (STACK_SIZE-1)) != 0 )
> panic("Misaligned CPU0 stack.");
>
> - if ( efi_loader )
> + if ( efi_platform )
> {
> - set_pdx_range(xen_phys_start >> PAGE_SHIFT,
> - (xen_phys_start + BOOTSTRAP_MAP_BASE) >> PAGE_SHIFT);
> + if ( efi_loader )
> + {
> + set_pdx_range(xen_phys_start >> PAGE_SHIFT,
> + (xen_phys_start + BOOTSTRAP_MAP_BASE) >>
> PAGE_SHIFT);
>
> - /* Clean up boot loader identity mappings. */
> - destroy_xen_mappings(xen_phys_start,
> - xen_phys_start + BOOTSTRAP_MAP_BASE);
> + /* Clean up boot loader identity mappings. */
> + destroy_xen_mappings(xen_phys_start,
> + xen_phys_start + BOOTSTRAP_MAP_BASE);
>
> - /* Make boot page tables match non-EFI boot. */
> - l3_bootmap[l3_table_offset(BOOTSTRAP_MAP_BASE)] =
> - l3e_from_paddr(__pa(l2_bootmap), __PAGE_HYPERVISOR);
> + /* Make boot page tables match non-EFI boot. */
> + l3_bootmap[l3_table_offset(BOOTSTRAP_MAP_BASE)] =
> + l3e_from_paddr(__pa(l2_bootmap), __PAGE_HYPERVISOR);
> + }
>
> - memmap_type = loader;
> + memmap_type = "EFI";
> }
> else if ( e820_raw_nr != 0 )
> {
> diff --git a/xen/arch/x86/x86_64/asm-offsets.c
> b/xen/arch/x86/x86_64/asm-offsets.c
> index ca3712f..d27596b 100644
> --- a/xen/arch/x86/x86_64/asm-offsets.c
> +++ b/xen/arch/x86/x86_64/asm-offsets.c
> @@ -172,4 +172,6 @@ void __dummy__(void)
> DEFINE(MB2_fixed_sizeof, sizeof(multiboot2_fixed_t));
> OFFSET(MB2_tag_size, multiboot2_tag_t, size);
> OFFSET(MB2_mem_lower, multiboot2_tag_basic_meminfo_t, mem_lower);
> + OFFSET(MB2_efi64_st, multiboot2_tag_efi64_t, pointer);
> + OFFSET(MB2_efi64_ih, multiboot2_tag_efi64_ih_t, pointer);
> }
> diff --git a/xen/common/efi/boot.c b/xen/common/efi/boot.c
> index f8be3dd..c5725ca 100644
> --- a/xen/common/efi/boot.c
> +++ b/xen/common/efi/boot.c
> @@ -75,6 +75,17 @@ static size_t wstrlen(const CHAR16 * s);
> static int set_color(u32 mask, int bpp, u8 *pos, u8 *sz);
> static bool_t match_guid(const EFI_GUID *guid1, const EFI_GUID *guid2);
>
> +static void efi_init(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable);
> +static void efi_console_set_mode(void);
> +static EFI_GRAPHICS_OUTPUT_PROTOCOL *efi_get_gop(void);
> +static UINTN efi_find_gop_mode(EFI_GRAPHICS_OUTPUT_PROTOCOL *gop,
> + UINTN cols, UINTN rows, UINTN depth);
> +static void efi_tables(void);
> +static void setup_efi_pci(void);
> +static void efi_variables(void);
> +static void efi_set_gop_mode(EFI_GRAPHICS_OUTPUT_PROTOCOL *gop, UINTN
> gop_mode);
> +static void efi_exit_boot(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE
> *SystemTable);
> +
If any of these forward declarations are needed, they should be
introduced in the appropriate create efi_$FOO patch. However, I can't
spot a need for any of them.
~Andrew
> static const EFI_BOOT_SERVICES *__initdata efi_bs;
> static EFI_HANDLE __initdata efi_ih;
>
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