[U-Boot] [PATCH 43/48] x86: Handle running as EFI payload

[Simon Glass]

Hi Bin,

On 24 July 2015 at 02:58, Bin Meng <bmeng.cn at gmail.com> wrote:
> Hi Simon,
>
> On Wed, Jul 22, 2015 at 11:49 PM, Simon Glass <sjg at chromium.org> wrote:
>> When U-Boot runs as an EFI payload it needs to avoid setting up the CPU
>> again. Also U-Boot currently does not handle interrupts for many devices, so
>> run with interrupts disabled.
>>
>> Signed-off-by: Simon Glass <sjg at chromium.org>
>> ---
>>
>>  arch/x86/Kconfig          | 16 ++++++++++++++++
>>  arch/x86/cpu/cpu.c        | 21 +++++++++++++--------
>>  arch/x86/cpu/interrupts.c | 10 ++++++++--
>>  arch/x86/lib/bootm.c      |  2 ++
>>  4 files changed, 39 insertions(+), 10 deletions(-)
>>
>> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
>> index f124d58..c64c626 100644
>> --- a/arch/x86/Kconfig
>> +++ b/arch/x86/Kconfig
>> @@ -194,6 +194,7 @@ config X86_RAMTEST
>>
>>  config HAVE_FSP
>>         bool "Add an Firmware Support Package binary"
>> +       depends on !EFI
>>         help
>>           Select this option to add an Firmware Support Package binary to
>>           the resulting U-Boot image. It is a binary blob which U-Boot uses
>> @@ -309,6 +310,7 @@ menu "System tables"
>>
>>  config GENERATE_PIRQ_TABLE
>>         bool "Generate a PIRQ table"
>> +       depends on !EFI
>>         default n
>>         help
>>           Generate a PIRQ routing table for this board. The PIRQ routing table
>> @@ -319,6 +321,7 @@ config GENERATE_PIRQ_TABLE
>>
>>  config GENERATE_SFI_TABLE
>>         bool "Generate a SFI (Simple Firmware Interface) table"
>> +       depends on !EFI
>>         help
>>           The Simple Firmware Interface (SFI) provides a lightweight method
>>           for platform firmware to pass information to the operating system
>> @@ -333,6 +336,7 @@ config GENERATE_SFI_TABLE
>>
>>  config GENERATE_MP_TABLE
>>         bool "Generate an MP (Multi-Processor) table"
>> +       depends on !EFI
>>         default n
>>         help
>>           Generate an MP (Multi-Processor) table for this board. The MP table
>> @@ -383,4 +387,16 @@ config PCIE_ECAM_SIZE
>>           so a default 0x10000000 size covers all of the 256 buses which is the
>>           maximum number of PCI buses as defined by the PCI specification.
>>
>> +if EFI
>> +
>> +config SYS_CAR_ADDR
>> +       hex
>> +       default 0x100000
>> +
>> +config SYS_CAR_SIZE
>> +       hex
>> +       default 0x20000
>> +
>> +endif
>
> Can we move this to arch/x86/cpu/efi/Kconfig?

That's for the application (i.e. the 'cpu' is EFI). These options are
actually needed for the payload. I'll move them to
arch/x86/lib/efi/Kconfig since it is reasonable to include that for
all x86 boards.

>
>> +
>>  endmenu
>> diff --git a/arch/x86/cpu/cpu.c b/arch/x86/cpu/cpu.c
>> index d233a45..129777c 100644
>> --- a/arch/x86/cpu/cpu.c
>> +++ b/arch/x86/cpu/cpu.c
>> @@ -330,13 +330,15 @@ int x86_cpu_init_f(void)
>>         const u32 em_rst = ~X86_CR0_EM;
>>         const u32 mp_ne_set = X86_CR0_MP | X86_CR0_NE;
>>
>> -       /* initialize FPU, reset EM, set MP and NE */
>> -       asm ("fninit\n" \
>> -            "movl %%cr0, %%eax\n" \
>> -            "andl %0, %%eax\n" \
>> -            "orl  %1, %%eax\n" \
>> -            "movl %%eax, %%cr0\n" \
>> -            : : "i" (em_rst), "i" (mp_ne_set) : "eax");
>> +       if (ll_boot_init()) {
>> +               /* initialize FPU, reset EM, set MP and NE */
>> +               asm ("fninit\n" \
>> +               "movl %%cr0, %%eax\n" \
>> +               "andl %0, %%eax\n" \
>> +               "orl  %1, %%eax\n" \
>> +               "movl %%eax, %%cr0\n" \
>> +               : : "i" (em_rst), "i" (mp_ne_set) : "eax");
>> +       }
>>
>>         /* identify CPU via cpuid and store the decoded info into gd->arch */
>>         if (has_cpuid()) {
>> @@ -712,5 +714,8 @@ __weak int x86_init_cpus(void)
>>
>>  int cpu_init_r(void)
>>  {
>> -       return x86_init_cpus();
>> +       if (ll_boot_init())
>> +               return x86_init_cpus();
>> +
>> +       return 0;
>>  }
>> diff --git a/arch/x86/cpu/interrupts.c b/arch/x86/cpu/interrupts.c
>> index a86c673..7df50bd 100644
>> --- a/arch/x86/cpu/interrupts.c
>> +++ b/arch/x86/cpu/interrupts.c
>> @@ -254,8 +254,14 @@ int interrupt_init(void)
>>         /* Initialize core interrupt and exception functionality of CPU */
>>         cpu_init_interrupts();
>>
>> -       /* It is now safe to enable interrupts */
>> -       enable_interrupts();
>> +       /*
>> +        * It is now safe to enable interrupts.
>> +        *
>> +        * TODO(sjg at chromium.org): But we don't handle these correctly when
>> +        * booted from EFI.
>> +        */
>> +       if (ll_boot_init())
>> +               enable_interrupts();
>>  #endif
>>
>>         return 0;
>> diff --git a/arch/x86/lib/bootm.c b/arch/x86/lib/bootm.c
>> index 445ee6e..3ad941f 100644
>> --- a/arch/x86/lib/bootm.c
>> +++ b/arch/x86/lib/bootm.c
>> @@ -165,6 +165,7 @@ int boot_linux_kernel(ulong setup_base, ulong load_address, bool image_64bit)
>>                 * U-boot is setting them up that way for itself in
>>                 * arch/i386/cpu/cpu.c.
>>                 */
>> +#ifndef CONFIG_ARCH_EFI
>
> Does this mean EFI application cannot load a Linux kernel?

Yes. I'll add a comment. It would actually be possible to implement
this, but it is not done yet.

>
>>                 __asm__ __volatile__ (
>>                 "movl $0, %%ebp\n"
>>                 "cli\n"
>> @@ -173,6 +174,7 @@ int boot_linux_kernel(ulong setup_base, ulong load_address, bool image_64bit)
>>                 [boot_params] "S"(setup_base),
>>                 "b"(0), "D"(0)
>>                 );
>> +#endif
>>         }
>>
>>         /* We can't get to here */
>> --
>
> Regards,
> Bin

Regards,
Simon