From patchwork Wed Jan 4 19:59:45 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Graeme Russ X-Patchwork-Id: 134342 X-Patchwork-Delegate: graeme.russ@gmail.com Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from theia.denx.de (theia.denx.de [85.214.87.163]) by ozlabs.org (Postfix) with ESMTP id 9AC8EB6FA8 for ; Thu, 5 Jan 2012 07:01:15 +1100 (EST) Received: from localhost (localhost [127.0.0.1]) by theia.denx.de (Postfix) with ESMTP id 6EDD628445; Wed, 4 Jan 2012 21:00:47 +0100 (CET) X-Virus-Scanned: Debian amavisd-new at theia.denx.de Received: from theia.denx.de ([127.0.0.1]) by localhost (theia.denx.de [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id pQSAix9IFt-N; Wed, 4 Jan 2012 21:00:47 +0100 (CET) Received: from theia.denx.de (localhost [127.0.0.1]) by theia.denx.de (Postfix) with ESMTP id 721602841A; Wed, 4 Jan 2012 21:00:33 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by theia.denx.de (Postfix) with ESMTP id 240352841A for ; Wed, 4 Jan 2012 21:00:31 +0100 (CET) X-Virus-Scanned: Debian amavisd-new at theia.denx.de Received: from theia.denx.de ([127.0.0.1]) by localhost (theia.denx.de [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id iAOmJ1v2q89f for ; Wed, 4 Jan 2012 21:00:30 +0100 (CET) X-policyd-weight: NOT_IN_SBL_XBL_SPAMHAUS=-1.5 NOT_IN_SPAMCOP=-1.5 NOT_IN_BL_NJABL=-1.5 (only DNSBL check requested) Received: from mail-vx0-f172.google.com (mail-vx0-f172.google.com [209.85.220.172]) by theia.denx.de (Postfix) with ESMTPS id 5AB6E283F0 for ; Wed, 4 Jan 2012 21:00:19 +0100 (CET) Received: by mail-vx0-f172.google.com with SMTP id fk13so13532083vcb.3 for ; Wed, 04 Jan 2012 12:00:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to:references :in-reply-to; bh=rmOB7UXP0MMyRgV8Zzo3po/R9qLYv7K4v4jcaNlSCWg=; b=L0dNzxIQihK2kmJHyZVzTGI+uKz7EN10JBc8dS+lV7jKxH12uN63FpA6XC8TQLqk/I /HUqbTGjK7BO0LEr5E/wxpVXTgs2YQ0lbxchKmumkkOko8pntoRtg58yQIgTwxFDpH4P LeD/xWRxT/t85+gGlPqHtvUulTcG6tYJvTDew= Received: by 10.220.107.73 with SMTP id a9mr33766088vcp.11.1325707219025; Wed, 04 Jan 2012 12:00:19 -0800 (PST) Received: from localhost.localdomain (d110-32-162-141.sbr801.nsw.optusnet.com.au. [110.32.162.141]) by mx.google.com with ESMTPS id eb3sm33049296vdc.5.2012.01.04.12.00.16 (version=SSLv3 cipher=OTHER); Wed, 04 Jan 2012 12:00:18 -0800 (PST) From: Graeme Russ To: u-boot@lists.denx.de Date: Thu, 5 Jan 2012 06:59:45 +1100 Message-Id: <1325707195-3218-7-git-send-email-graeme.russ@gmail.com> X-Mailer: git-send-email 1.7.5.2.317.g391b14 In-Reply-To: <1325707195-3218-1-git-send-email-graeme.russ@gmail.com> References: <1325707195-3218-1-git-send-email-graeme.russ@gmail.com> In-Reply-To: <1325477374-6417-8-git-send-email-graeme.russ@gmail.com> Subject: [U-Boot] [PATCH v2 07/17] x86: Use fs for global data X-BeenThere: u-boot@lists.denx.de X-Mailman-Version: 2.1.11 Precedence: list List-Id: U-Boot discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: u-boot-bounces@lists.denx.de Errors-To: u-boot-bounces@lists.denx.de Use the base address of the 'F' segment as a pointer to the global data structure. By adding the linear address (i.e. the 'D' segment address) as the first word of the global data structure, the address of the global data relative to the 'D' segment can be found simply, for example, by: fs movl 0, %eax This makes the gd 'pointer' writable prior to relocation (by reloading the Global Descriptor Table) which brings x86 into line with all other arches NOTE: Writing to the gd 'pointer' is expensive (but we only do it twice) but using it to access global data members (read and write) is still fairly cheap Signed-off-by: Graeme Russ Acked-by: Simon Glass --- Changes for v2: - Rebased against changes made to patch #3 - Removed extra indent - Tweaked commit message arch/x86/cpu/cpu.c | 53 ++++++++++++++++++++-------------- arch/x86/cpu/start.S | 8 ++++- arch/x86/include/asm/global_data.h | 21 +++++++++---- arch/x86/include/asm/processor.h | 1 + arch/x86/include/asm/u-boot-x86.h | 2 + arch/x86/lib/board.c | 56 +++++++++++++++++++++++++----------- 6 files changed, 94 insertions(+), 47 deletions(-) -- 1.7.5.2.317.g391b14 diff --git a/arch/x86/cpu/cpu.c b/arch/x86/cpu/cpu.c index 8102fb9..8c3b92c 100644 --- a/arch/x86/cpu/cpu.c +++ b/arch/x86/cpu/cpu.c @@ -90,6 +90,37 @@ static void load_gdt(const u64 *boot_gdt, u16 num_entries) asm volatile("lgdtl %0\n" : : "m" (gdt)); } +void init_gd(gd_t *id, u64 *gdt_addr) +{ + id->gd_addr = (ulong)id; + setup_gdt(id, gdt_addr); +} + +void setup_gdt(gd_t *id, u64 *gdt_addr) +{ + /* CS: code, read/execute, 4 GB, base 0 */ + gdt_addr[X86_GDT_ENTRY_32BIT_CS] = GDT_ENTRY(0xc09b, 0, 0xfffff); + + /* DS: data, read/write, 4 GB, base 0 */ + gdt_addr[X86_GDT_ENTRY_32BIT_DS] = GDT_ENTRY(0xc093, 0, 0xfffff); + + /* FS: data, read/write, 4 GB, base (Global Data Pointer) */ + gdt_addr[X86_GDT_ENTRY_32BIT_FS] = GDT_ENTRY(0xc093, (ulong)id, 0xfffff); + + /* 16-bit CS: code, read/execute, 64 kB, base 0 */ + gdt_addr[X86_GDT_ENTRY_16BIT_CS] = GDT_ENTRY(0x109b, 0, 0x0ffff); + + /* 16-bit DS: data, read/write, 64 kB, base 0 */ + gdt_addr[X86_GDT_ENTRY_16BIT_DS] = GDT_ENTRY(0x1093, 0, 0x0ffff); + + load_gdt(gdt_addr, X86_GDT_NUM_ENTRIES); + load_ds(X86_GDT_ENTRY_32BIT_DS); + load_es(X86_GDT_ENTRY_32BIT_DS); + load_gs(X86_GDT_ENTRY_32BIT_DS); + load_ss(X86_GDT_ENTRY_32BIT_DS); + load_fs(X86_GDT_ENTRY_32BIT_FS); +} + int x86_cpu_init_f(void) { const u32 em_rst = ~X86_CR0_EM; @@ -117,28 +148,6 @@ int x86_cpu_init_r(void) "movl %%eax, %%cr0\n" "wbinvd\n" : : "i" (nw_cd_rst) : "eax"); - /* - * There are machines which are known to not boot with the GDT - * being 8-byte unaligned. Intel recommends 16 byte alignment - */ - static const u64 boot_gdt[] __aligned(16) = { - /* CS: code, read/execute, 4 GB, base 0 */ - [X86_GDT_ENTRY_32BIT_CS] = GDT_ENTRY(0xc09b, 0, 0xfffff), - /* DS: data, read/write, 4 GB, base 0 */ - [X86_GDT_ENTRY_32BIT_DS] = GDT_ENTRY(0xc093, 0, 0xfffff), - /* 16-bit CS: code, read/execute, 64 kB, base 0 */ - [X86_GDT_ENTRY_16BIT_CS] = GDT_ENTRY(0x109b, 0, 0x0ffff), - /* 16-bit DS: data, read/write, 64 kB, base 0 */ - [X86_GDT_ENTRY_16BIT_DS] = GDT_ENTRY(0x1093, 0, 0x0ffff), - }; - - load_gdt(boot_gdt, X86_GDT_NUM_ENTRIES); - load_ds(X86_GDT_ENTRY_32BIT_DS); - load_es(X86_GDT_ENTRY_32BIT_DS); - load_fs(X86_GDT_ENTRY_32BIT_DS); - load_gs(X86_GDT_ENTRY_32BIT_DS); - load_ss(X86_GDT_ENTRY_32BIT_DS); - /* Initialize core interrupt and exception functionality of CPU */ cpu_init_interrupts(); return 0; diff --git a/arch/x86/cpu/start.S b/arch/x86/cpu/start.S index 69a9b2c..ee0dabe 100644 --- a/arch/x86/cpu/start.S +++ b/arch/x86/cpu/start.S @@ -31,7 +31,7 @@ #include #include #include -#include +#include .section .text .code32 @@ -85,6 +85,12 @@ car_init_ret: */ movl $CONFIG_SYS_INIT_SP_ADDR, %esp + /* Initialise the Global Data Pointer */ + movl $CONFIG_SYS_INIT_GD_ADDR, %eax + movl %eax, %edx + addl $GENERATED_GBL_DATA_SIZE, %edx + call init_gd; + /* Set parameter to board_init_f() to boot flags */ xorl %eax, %eax movw %bx, %ax diff --git a/arch/x86/include/asm/global_data.h b/arch/x86/include/asm/global_data.h index 05a2139..908a02c 100644 --- a/arch/x86/include/asm/global_data.h +++ b/arch/x86/include/asm/global_data.h @@ -36,6 +36,8 @@ #ifndef __ASSEMBLY__ typedef struct global_data { + /* NOTE: gd_addr MUST be first member of struct global_data! */ + unsigned long gd_addr; /* Location of Global Data */ bd_t *bd; unsigned long flags; unsigned long baudrate; @@ -51,13 +53,24 @@ typedef struct global_data { unsigned long bus_clk; unsigned long relocaddr; /* Start address of U-Boot in RAM */ unsigned long start_addr_sp; /* start_addr_stackpointer */ + unsigned long gdt_addr; /* Location of GDT */ + unsigned long new_gd_addr; /* New location of Global Data */ phys_size_t ram_size; /* RAM size */ unsigned long reset_status; /* reset status register at boot */ void **jt; /* jump table */ char env_buf[32]; /* buffer for getenv() before reloc. */ } gd_t; -extern gd_t *gd; +static inline gd_t *get_fs_gd_ptr(void) +{ + gd_t *gd_ptr; + + asm volatile("fs movl 0, %0\n" : "=r" (gd_ptr)); + + return gd_ptr; +} + +#define gd get_fs_gd_ptr() #endif @@ -73,12 +86,6 @@ extern gd_t *gd; #define GD_FLG_DISABLE_CONSOLE 0x00040 /* Disable console (in & out) */ #define GD_FLG_ENV_READY 0x00080 /* Environment imported into hash table */ -#if 0 #define DECLARE_GLOBAL_DATA_PTR -#else -#define XTRN_DECLARE_GLOBAL_DATA_PTR extern -#define DECLARE_GLOBAL_DATA_PTR XTRN_DECLARE_GLOBAL_DATA_PTR \ -gd_t *gd -#endif #endif /* __ASM_GBL_DATA_H */ diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index aa8188e..6eb5180 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -33,6 +33,7 @@ enum { X86_GDT_ENTRY_UNUSED, X86_GDT_ENTRY_32BIT_CS, X86_GDT_ENTRY_32BIT_DS, + X86_GDT_ENTRY_32BIT_FS, X86_GDT_ENTRY_16BIT_CS, X86_GDT_ENTRY_16BIT_DS, X86_GDT_NUM_ENTRIES diff --git a/arch/x86/include/asm/u-boot-x86.h b/arch/x86/include/asm/u-boot-x86.h index c3d2277..5540d51 100644 --- a/arch/x86/include/asm/u-boot-x86.h +++ b/arch/x86/include/asm/u-boot-x86.h @@ -37,6 +37,8 @@ int x86_cpu_init_r(void); int cpu_init_r(void); int x86_cpu_init_f(void); int cpu_init_f(void); +void init_gd(gd_t *id, u64 *gdt_addr); +void setup_gdt(gd_t *id, u64 *gdt_addr); /* cpu/.../timer.c */ void timer_isr(void *); diff --git a/arch/x86/lib/board.c b/arch/x86/lib/board.c index 6f075b7..b64c2d3 100644 --- a/arch/x86/lib/board.c +++ b/arch/x86/lib/board.c @@ -42,20 +42,12 @@ #include #include #include +#include #ifdef CONFIG_BITBANGMII #include #endif -/* - * Pointer to initial global data area - * - * Here we initialize it. - */ -#undef XTRN_DECLARE_GLOBAL_DATA_PTR -#define XTRN_DECLARE_GLOBAL_DATA_PTR /* empty = allocate here */ -DECLARE_GLOBAL_DATA_PTR = (gd_t *) (CONFIG_SYS_INIT_GD_ADDR); - /************************************************************************ * Init Utilities * ************************************************************************ @@ -128,6 +120,7 @@ static int calculate_relocation_address(void); static int copy_uboot_to_ram(void); static int clear_bss(void); static int do_elf_reloc_fixups(void); +static int copy_gd_to_ram(void); init_fnc_t *init_sequence_f[] = { cpu_init_f, @@ -146,6 +139,7 @@ init_fnc_t *init_sequence_f[] = { }; init_fnc_t *init_sequence_r[] = { + copy_gd_to_ram, cpu_init_r, /* basic cpu dependent setup */ board_early_init_r, /* basic board dependent setup */ dram_init, /* configure available RAM banks */ @@ -157,8 +151,6 @@ init_fnc_t *init_sequence_r[] = { NULL, }; -gd_t *gd; - static int calculate_relocation_address(void) { ulong text_start = (ulong)&__text_start; @@ -171,8 +163,18 @@ static int calculate_relocation_address(void) * requirements */ - /* Stack is at top of available memory */ + /* Global Data is at top of available memory */ dest_addr = gd->ram_size; + dest_addr -= GENERATED_GBL_DATA_SIZE; + dest_addr &= ~15; + gd->new_gd_addr = dest_addr; + + /* GDT is below Global Data */ + dest_addr -= X86_GDT_SIZE; + dest_addr &= ~15; + gd->gdt_addr = dest_addr; + + /* Stack is below GDT */ gd->start_addr_sp = dest_addr; /* U-Boot is below the stack */ @@ -279,6 +281,31 @@ void board_init_f_r(void) ; } +static int copy_gd_to_ram(void) +{ + gd_t *ram_gd; + + /* + * Global data is still in temporary memory (the CPU cache). + * calculate_relocation_address() has set gd->new_gd_addr to + * where the global data lives in RAM but getting it there + * safely is a bit tricky due to the 'F-Segment Hack' that + * we need to use for x86 + */ + ram_gd = (gd_t *)gd->new_gd_addr; + memcpy((void *)ram_gd, gd, sizeof(gd_t)); + + /* + * Reload the Global Descriptor Table so FS points to the + * in-RAM copy of Global Data (calculate_relocation_address() + * has already calculated the in-RAM location of the GDT) + */ + ram_gd->gd_addr = (ulong)ram_gd; + init_gd(ram_gd, (u64 *)gd->gdt_addr); + + return 0; +} + void board_init_r(gd_t *id, ulong dest_addr) { #if defined(CONFIG_CMD_NET) @@ -288,15 +315,10 @@ void board_init_r(gd_t *id, ulong dest_addr) ulong size; #endif static bd_t bd_data; - static gd_t gd_data; init_fnc_t **init_fnc_ptr; show_boot_progress(0x21); - /* Global data pointer is now writable */ - gd = &gd_data; - memcpy(gd, id, sizeof(gd_t)); - /* compiler optimization barrier needed for GCC >= 3.4 */ __asm__ __volatile__("" : : : "memory");