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([185.25.67.249]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-a9392f5485asm325846666b.88.2024.09.26.02.21.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 26 Sep 2024 02:21:19 -0700 (PDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: b1474486-7be8-11ef-99a2-01e77a169b0f DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cloud.com; s=cloud; t=1727342480; x=1727947280; darn=lists.xenproject.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=RE9zPGw7uXdaStphlidPBgHBY1QIBKq37/9PhyIL3ZI=; b=fBtfzHfVf5rmKM7MW8IpwtebkxAHajLldhrriT2w7cEPXxmW7MSWmLRi3fhs8WiGD8 Kjo7sTUFAhc7XpgIEILH4WV82A+AMQL5v3Va+sYlmcNTXOCgt6Zq73SbsuIewAXWdiyA DI0m+UJGP4Dr2thSf0W0Sag1k4p/La33qciJ4= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1727342480; x=1727947280; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=RE9zPGw7uXdaStphlidPBgHBY1QIBKq37/9PhyIL3ZI=; b=KBSrgXqR0fjNqbuiLOtaL2G7FL9ALwZeHvF/xLPcw2DCJktfGBLZXYWyW94TQi6b0z ZK1+Pa8q5PsRKPdRHYBGbb0W3HTMmiCw4ZfUDekzWIN+qJpesE62LaClWswS03IWGB7L vTmjyLakLYPnstGgp3821KU8hihsWcw0WslKjEZHM8Io4XQqGnRBNJNS1/XlNqJFJTP9 1Ma3W6IVaf1GSgcxKhQ9/cXcNCFk8kr6MqU4sGrD6+sn3p8A2GMbdCu0YgAY9z+1DNlB cKTB6RvDOd7phyY9zJ813LymyOrw7D9UcJKNCI9h8YOyzoknuduHFmcz1Mh/xG8cBDGf dz5Q== X-Gm-Message-State: AOJu0YwtF8dbISkLC9GqXF4Xn93k6hRxRFxwKmexpapooLVV6HNUG+bW GplM7iw6oHYPUbLQVreFJna35QJmwACjiknqgqIM7HRm8h4j0ExZ7lGxsh2J8IGzA8xUbLadYyn p X-Google-Smtp-Source: AGHT+IHFRVspOhDtMBFEaXV9v9KX/s1hg6/MJiDsMDUeP1OVuCIzeO1tGRO0LmngKLBpGva0Xnpr8w== X-Received: by 2002:a17:907:3daa:b0:a86:6d39:cbfd with SMTP id a640c23a62f3a-a93a0682bd7mr583743166b.57.1727342480132; Thu, 26 Sep 2024 02:21:20 -0700 (PDT) From: Frediano Ziglio To: xen-devel@lists.xenproject.org Cc: Frediano Ziglio , Jan Beulich , Andrew Cooper , =?utf-8?q?Roger_Pau_Monn=C3=A9?= , "Daniel P. Smith" , =?utf-8?q?Marek_Marczykow?= =?utf-8?q?ski-G=C3=B3recki?= Subject: [PATCH v6 2/3] x86/boot: Rewrite EFI/MBI2 code partly in C Date: Thu, 26 Sep 2024 10:21:08 +0100 Message-Id: <20240926092109.475271-3-frediano.ziglio@cloud.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240926092109.475271-1-frediano.ziglio@cloud.com> References: <20240926092109.475271-1-frediano.ziglio@cloud.com> MIME-Version: 1.0 No need to have it coded in assembly. Signed-off-by: Frediano Ziglio --- Changes since v1: - update some comments; - explain why %ebx is saved before calling efi_parse_mbi2; - move lea before test instruction; - removed asmlinkage from efi_multiboot2 and add to efi_parse_mbi2; - fix line length; - update an error message specifying "Multiboot2" instead of "Multiboot"; - use obj-bin-X instead of obj-X in Makefile; - avoid restoring %eax (MBI magic). Changes since v3: - rename new function to efi_multiboot2_prelude; - declare efi_multiboot2 in a separate header. Changes since v4: - fix some style and space; - fix MISRA requirement. --- xen/arch/x86/boot/head.S | 142 +++++++-------------------------- xen/arch/x86/efi/Makefile | 1 + xen/arch/x86/efi/efi-boot.h | 6 +- xen/arch/x86/efi/parse-mbi2.c | 63 +++++++++++++++ xen/arch/x86/efi/stub.c | 3 +- xen/arch/x86/include/asm/efi.h | 18 +++++ 6 files changed, 115 insertions(+), 118 deletions(-) create mode 100644 xen/arch/x86/efi/parse-mbi2.c create mode 100644 xen/arch/x86/include/asm/efi.h diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S index e0901ee400..89b5e2af88 100644 --- a/xen/arch/x86/boot/head.S +++ b/xen/arch/x86/boot/head.S @@ -121,8 +121,6 @@ multiboot2_header: .Lbad_cpu_msg: .asciz "ERR: Not a 64-bit CPU!" .Lbad_ldr_msg: .asciz "ERR: Not a Multiboot bootloader!" .Lbad_ldr_nbs: .asciz "ERR: Bootloader shutdown EFI x64 boot services!" -.Lbad_ldr_nst: .asciz "ERR: EFI SystemTable is not provided by bootloader!" -.Lbad_ldr_nih: .asciz "ERR: EFI ImageHandle is not provided by bootloader!" .Lbad_efi_msg: .asciz "ERR: EFI IA-32 platforms are not supported!" .Lbag_alg_msg: .asciz "ERR: Xen must be loaded at a 2Mb boundary!" .Lno_nx_msg: .asciz "ERR: Not an NX-capable CPU!" @@ -161,17 +159,6 @@ early_error: /* Here to improve the disassembly. */ mov $sym_offs(.Lno_nx_msg), %ecx jmp .Lget_vtb #endif -.Lmb2_no_st: - /* - * Here we are on EFI platform. vga_text_buffer was zapped earlier - * because there is pretty good chance that VGA is unavailable. - */ - mov $sym_offs(.Lbad_ldr_nst), %ecx - jmp .Lget_vtb -.Lmb2_no_ih: - /* Ditto. */ - mov $sym_offs(.Lbad_ldr_nih), %ecx - jmp .Lget_vtb .Lmb2_no_bs: /* * Ditto. Additionally, here there is a chance that Xen was started @@ -189,6 +176,10 @@ early_error: /* Here to improve the disassembly. */ mov $sym_offs(.Lbad_efi_msg), %ecx xor %edi,%edi # No VGA text buffer jmp .Lprint_err +.Ldirect_error: + mov sym_esi(vga_text_buffer), %edi + mov %eax, %esi + jmp 1f .Lget_vtb: mov sym_esi(vga_text_buffer), %edi .Lprint_err: @@ -235,7 +226,7 @@ __efi64_mb2_start: /* * Align the stack as UEFI spec requires. Keep it aligned - * before efi_multiboot2() call by pushing/popping even + * before efi_multiboot2_prelude() call by pushing/popping even * numbers of items on it. */ and $~15, %rsp @@ -243,7 +234,7 @@ __efi64_mb2_start: /* * Initialize BSS (no nasty surprises!). * It must be done earlier than in BIOS case - * because efi_multiboot2() touches it. + * because efi_multiboot2_prelude() touches it. */ mov %eax, %edx lea __bss_start(%rip), %edi @@ -252,36 +243,30 @@ __efi64_mb2_start: shr $3, %ecx xor %eax, %eax rep stosq - mov %edx, %eax - - /* Check for Multiboot2 bootloader. */ - cmp $MULTIBOOT2_BOOTLOADER_MAGIC,%eax - je .Lefi_multiboot2_proto - - /* Jump to .Lnot_multiboot after switching CPU to x86_32 mode. */ - lea .Lnot_multiboot(%rip), %r15 - jmp x86_32_switch - -.Lefi_multiboot2_proto: - /* Zero EFI SystemTable, EFI ImageHandle addresses and cmdline. */ - xor %esi,%esi - xor %edi,%edi - xor %edx,%edx - /* Skip Multiboot2 information fixed part. */ - lea (MB2_fixed_sizeof+MULTIBOOT2_TAG_ALIGN-1)(%rbx),%ecx - and $~(MULTIBOOT2_TAG_ALIGN-1),%ecx - -.Lefi_mb2_tsize: - /* Check Multiboot2 information total size. */ - mov %ecx,%r8d - sub %ebx,%r8d - cmp %r8d,MB2_fixed_total_size(%rbx) - jbe .Lrun_bs + /* + * Spill MB2 magic. + * Spill the pointer too, to keep the stack aligned. + */ + push %rdx + push %rbx - /* Are EFI boot services available? */ - cmpl $MULTIBOOT2_TAG_TYPE_EFI_BS,MB2_tag_type(%rcx) - jne .Lefi_mb2_st + /* + * efi_multiboot2_prelude() is called according to System V AMD64 ABI: + * - IN: %edi - Multiboot2 magic, + * %rsi - Multiboot2 pointer. + * - OUT: %rax - error string. + */ + mov %edx, %edi + mov %rbx, %rsi + call efi_multiboot2_prelude + lea .Ldirect_error(%rip), %r15 + test %rax, %rax + jnz x86_32_switch + + /* Restore Multiboot2 pointer and magic. */ + pop %rbx + pop %rax /* We are on EFI platform and EFI boot services are available. */ incb efi_platform(%rip) @@ -291,77 +276,6 @@ __efi64_mb2_start: * be run on EFI platforms. */ incb skip_realmode(%rip) - jmp .Lefi_mb2_next_tag - -.Lefi_mb2_st: - /* Get EFI SystemTable address from Multiboot2 information. */ - cmpl $MULTIBOOT2_TAG_TYPE_EFI64,MB2_tag_type(%rcx) - cmove MB2_efi64_st(%rcx),%rsi - je .Lefi_mb2_next_tag - - /* Get EFI ImageHandle address from Multiboot2 information. */ - cmpl $MULTIBOOT2_TAG_TYPE_EFI64_IH,MB2_tag_type(%rcx) - cmove MB2_efi64_ih(%rcx),%rdi - je .Lefi_mb2_next_tag - - /* Get command line from Multiboot2 information. */ - cmpl $MULTIBOOT2_TAG_TYPE_CMDLINE, MB2_tag_type(%rcx) - jne .Lno_cmdline - lea MB2_tag_string(%rcx), %rdx - jmp .Lefi_mb2_next_tag -.Lno_cmdline: - - /* Is it the end of Multiboot2 information? */ - cmpl $MULTIBOOT2_TAG_TYPE_END,MB2_tag_type(%rcx) - je .Lrun_bs - -.Lefi_mb2_next_tag: - /* Go to next Multiboot2 information tag. */ - add MB2_tag_size(%rcx),%ecx - add $(MULTIBOOT2_TAG_ALIGN-1),%ecx - and $~(MULTIBOOT2_TAG_ALIGN-1),%ecx - jmp .Lefi_mb2_tsize - -.Lrun_bs: - /* Are EFI boot services available? */ - cmpb $0,efi_platform(%rip) - - /* Jump to .Lmb2_no_bs after switching CPU to x86_32 mode. */ - lea .Lmb2_no_bs(%rip),%r15 - jz x86_32_switch - - /* Is EFI SystemTable address provided by boot loader? */ - test %rsi,%rsi - - /* Jump to .Lmb2_no_st after switching CPU to x86_32 mode. */ - lea .Lmb2_no_st(%rip),%r15 - jz x86_32_switch - - /* Is EFI ImageHandle address provided by boot loader? */ - test %rdi,%rdi - - /* Jump to .Lmb2_no_ih after switching CPU to x86_32 mode. */ - lea .Lmb2_no_ih(%rip),%r15 - jz x86_32_switch - - /* Save Multiboot2 magic on the stack. */ - push %rax - - /* Save EFI ImageHandle on the stack. */ - push %rdi - - /* - * efi_multiboot2() is called according to System V AMD64 ABI: - * - IN: %rdi - EFI ImageHandle, %rsi - EFI SystemTable, - * %rdx - MB2 cmdline - */ - call efi_multiboot2 - - /* Just pop an item from the stack. */ - pop %rax - - /* Restore Multiboot2 magic. */ - pop %rax /* Jump to trampoline_setup after switching CPU to x86_32 mode. */ lea trampoline_setup(%rip),%r15 diff --git a/xen/arch/x86/efi/Makefile b/xen/arch/x86/efi/Makefile index 24dfecfad1..51140061fc 100644 --- a/xen/arch/x86/efi/Makefile +++ b/xen/arch/x86/efi/Makefile @@ -14,5 +14,6 @@ $(addprefix $(obj)/,$(EFIOBJ-y)): CFLAGS_stack_boundary := $(cflags-stack-bounda obj-y := common-stub.o stub.o obj-$(XEN_BUILD_EFI) := $(filter-out %.init.o,$(EFIOBJ-y)) obj-bin-$(XEN_BUILD_EFI) := $(filter %.init.o,$(EFIOBJ-y)) +obj-bin-y += parse-mbi2.o extra-$(XEN_BUILD_EFI) += buildid.o relocs-dummy.o nocov-$(XEN_BUILD_EFI) += stub.o diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h index 7aa55e7aaf..859c01c13f 100644 --- a/xen/arch/x86/efi/efi-boot.h +++ b/xen/arch/x86/efi/efi-boot.h @@ -816,9 +816,9 @@ static const char *__init get_option(const char *cmd, const char *opt) return o; } -void asmlinkage __init efi_multiboot2(EFI_HANDLE ImageHandle, - EFI_SYSTEM_TABLE *SystemTable, - const char *cmdline) +void __init efi_multiboot2(EFI_HANDLE ImageHandle, + EFI_SYSTEM_TABLE *SystemTable, + const char *cmdline) { EFI_GRAPHICS_OUTPUT_PROTOCOL *gop; EFI_HANDLE gop_handle; diff --git a/xen/arch/x86/efi/parse-mbi2.c b/xen/arch/x86/efi/parse-mbi2.c new file mode 100644 index 0000000000..55a1777483 --- /dev/null +++ b/xen/arch/x86/efi/parse-mbi2.c @@ -0,0 +1,63 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#include +#include +#include +#include +#include + +const char * asmlinkage __init +efi_multiboot2_prelude(uint32_t magic, const multiboot2_fixed_t *mbi) +{ + const multiboot2_tag_t *tag; + EFI_HANDLE ImageHandle = NULL; + EFI_SYSTEM_TABLE *SystemTable = NULL; + const char *cmdline = NULL; + bool have_bs = false; + + if ( magic != MULTIBOOT2_BOOTLOADER_MAGIC ) + return "ERR: Not a Multiboot2 bootloader!"; + + /* Skip Multiboot2 information fixed part. */ + tag = _p(ROUNDUP((unsigned long)(mbi + 1), MULTIBOOT2_TAG_ALIGN)); + + for ( ; (const void *)tag - (const void *)mbi < mbi->total_size && + tag->type != MULTIBOOT2_TAG_TYPE_END; + tag = _p(ROUNDUP((unsigned long)tag + tag->size, + MULTIBOOT2_TAG_ALIGN)) ) + { + switch ( tag->type ) + { + case MULTIBOOT2_TAG_TYPE_EFI_BS: + have_bs = true; + break; + + case MULTIBOOT2_TAG_TYPE_EFI64: + SystemTable = _p(((const multiboot2_tag_efi64_t *)tag)->pointer); + break; + + case MULTIBOOT2_TAG_TYPE_EFI64_IH: + ImageHandle = _p(((const multiboot2_tag_efi64_ih_t *)tag)->pointer); + break; + + case MULTIBOOT2_TAG_TYPE_CMDLINE: + cmdline = ((const multiboot2_tag_string_t *)tag)->string; + break; + + default: + /* Satisfy MISRA requirement. */ + break; + } + } + + if ( !have_bs ) + return "ERR: Bootloader shutdown EFI x64 boot services!"; + if ( !SystemTable ) + return "ERR: EFI SystemTable is not provided by bootloader!"; + if ( !ImageHandle ) + return "ERR: EFI ImageHandle is not provided by bootloader!"; + + efi_multiboot2(ImageHandle, SystemTable, cmdline); + + return NULL; +} diff --git a/xen/arch/x86/efi/stub.c b/xen/arch/x86/efi/stub.c index 2cd5c8d4dc..27d40964d5 100644 --- a/xen/arch/x86/efi/stub.c +++ b/xen/arch/x86/efi/stub.c @@ -17,7 +17,8 @@ */ void __init noreturn efi_multiboot2(EFI_HANDLE ImageHandle, - EFI_SYSTEM_TABLE *SystemTable) + EFI_SYSTEM_TABLE *SystemTable, + const char *cmdline) { static const CHAR16 __initconst err[] = L"Xen does not have EFI code build in!\r\nSystem halted!\r\n"; diff --git a/xen/arch/x86/include/asm/efi.h b/xen/arch/x86/include/asm/efi.h new file mode 100644 index 0000000000..575a33e302 --- /dev/null +++ b/xen/arch/x86/include/asm/efi.h @@ -0,0 +1,18 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#ifndef X86_ASM_EFI_H +#define X86_ASM_EFI_H + +#include +#include +#include +#include +#include +#include +#include + +void efi_multiboot2(EFI_HANDLE ImageHandle, + EFI_SYSTEM_TABLE *SystemTable, + const char *cmdline); + +#endif /* X86_ASM_EFI_H */