x86, olpc: Add support for calling into OpenFirmware

Add support for saving OFW's cif, and later calling into it to run OFW commands. OFW remains resident in memory, living within virtual range 0xff800000 - 0xffc00000. A single page directory entry points to the pgdir that OFW actually uses, so rather than saving the entire page table, we grab and install that one entry permanently in the kernel's page table. This is currently only used by the OLPC XO. Note that this particular calling convention breaks PAE and PAT, and so cannot be used on newer x86 hardware. Signed-off-by: Andres Salomon <dilinger@queued.net> LKML-Reference: <20100618174653.7755a39a@dev.queued.net> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

x86, olpc: Add support for calling into OpenFirmware
Add support for saving OFW's cif, and later calling into it to run OFW commands. OFW remains resident in memory, living within virtual range 0xff800000 - 0xffc00000. A single page directory entry points to the pgdir that OFW actually uses, so rather than saving the entire page table, we grab and install that one entry permanently in the kernel's page table. This is currently only used by the OLPC XO. Note that this particular calling convention breaks PAE and PAT, and so cannot be used on newer x86 hardware. Signed-off-by: Andres Salomon <dilinger@queued.net> LKML-Reference: <20100618174653.7755a39a@dev.queued.net> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Andres Salomon · H. Peter Anvin
1 parent 7e27d6e778
Showing 9 changed files with 173 additions and 8 deletions Side-by-side Diff
Documentation/x86/zero-page.txt
arch/x86/Kconfig
arch/x86/include/asm/bootparam.h
arch/x86/include/asm/olpc_ofw.h
arch/x86/kernel/Makefile
arch/x86/kernel/head_32.S
arch/x86/kernel/olpc.c
arch/x86/kernel/olpc_ofw.c
arch/x86/kernel/setup.c
@@ -18,6 +18,7 @@
 080/010	ALL	hd0_info	hd0 disk parameter, OBSOLETE!!
 090/010	ALL	hd1_info	hd1 disk parameter, OBSOLETE!!
 0A0/010	ALL	sys_desc_table	System description table (struct sys_desc_table)
+0B0/010	ALL	olpc_ofw_header	OLPC's OpenFirmware CIF and friends
 140/080	ALL	edid_info	Video mode setup (struct edid_info)
 1C0/020	ALL	efi_info	EFI 32 information (struct efi_info)
 1E0/004	ALL	alk_mem_k	Alternative mem check, in KB
@@ -2062,6 +2062,15 @@
 	  Add support for detecting the unique features of the OLPC
 	  XO hardware.
  
+config OLPC_OPENFIRMWARE
+	bool "Support for OLPC's Open Firmware"
+	depends on !X86_64 && !X86_PAE
+	default y if OLPC
+	help
+	  This option adds support for the implementation of Open Firmware
+	  that is used on the OLPC XO-1 Children's Machine.
+	  If unsure, say N here.
+
 endif # X86_32
  
 config K8_NB
@@ -70,6 +70,14 @@
 	__u8  table[14];
 };
  
+/* Gleaned from OFW's set-parameters in cpu/x86/pc/linux.fth */
+struct olpc_ofw_header {
+	__u32 ofw_magic;	/* OFW signature */
+	__u32 ofw_version;
+	__u32 cif_handler;	/* callback into OFW */
+	__u32 irq_desc_table;
+} __attribute__((packed));
+
 struct efi_info {
 	__u32 efi_loader_signature;
 	__u32 efi_systab;
@@ -92,7 +100,8 @@
 	__u8  hd0_info[16];	/* obsolete! */		/* 0x080 */
 	__u8  hd1_info[16];	/* obsolete! */		/* 0x090 */
 	struct sys_desc_table sys_desc_table;		/* 0x0a0 */
-	__u8  _pad4[144];				/* 0x0b0 */
+	struct olpc_ofw_header olpc_ofw_header;		/* 0x0b0 */
+	__u8  _pad4[128];				/* 0x0c0 */
 	struct edid_info edid_info;			/* 0x140 */
 	struct efi_info efi_info;			/* 0x1c0 */
 	__u32 alt_mem_k;				/* 0x1e0 */
+#ifndef _ASM_X86_OLPC_OFW_H
+#define _ASM_X86_OLPC_OFW_H
+
+/* index into the page table containing the entry OFW occupies */
+#define OLPC_OFW_PDE_NR 1022
+
+#define OLPC_OFW_SIG 0x2057464F	/* aka "OFW " */
+
+#ifdef CONFIG_OLPC_OPENFIRMWARE
+
+/* run an OFW command by calling into the firmware */
+#define olpc_ofw(name, args, res) \
+	__olpc_ofw((name), ARRAY_SIZE(args), args, ARRAY_SIZE(res), res)
+
+extern int __olpc_ofw(const char *name, int nr_args, void **args, int nr_res,
+		void **res);
+
+/* determine whether OFW is available and lives in the proper memory */
+extern void olpc_ofw_detect(void);
+
+/* install OFW's pde permanently into the kernel's pgtable */
+extern void setup_olpc_ofw_pgd(void);
+
+#else /* !CONFIG_OLPC_OPENFIRMWARE */
+
+static inline void olpc_ofw_detect(void) { }
+static inline void setup_olpc_ofw_pgd(void) { }
+
+#endif /* !CONFIG_OLPC_OPENFIRMWARE */
+
+#endif /* _ASM_X86_OLPC_OFW_H */
@@ -104,6 +104,7 @@
 scx200-y			+= scx200_32.o
  
 obj-$(CONFIG_OLPC)		+= olpc.o
+obj-$(CONFIG_OLPC_OPENFIRMWARE)	+= olpc_ofw.o
 obj-$(CONFIG_X86_MRST)		+= mrst.o
  
 microcode-y				:= microcode_core.o
@@ -131,6 +131,12 @@
 	movsl
 1:
  
+#ifdef CONFIG_OLPC_OPENFIRMWARE
+	/* save OFW's pgdir table for later use when calling into OFW */
+	movl %cr3, %eax
+	movl %eax, pa(olpc_ofw_pgd)
+#endif
+
 #ifdef CONFIG_PARAVIRT
 	/* This is can only trip for a broken bootloader... */
 	cmpw $0x207, pa(boot_params + BP_version)
@@ -21,11 +21,8 @@
 #include <asm/geode.h>
 #include <asm/setup.h>
 #include <asm/olpc.h>
+#include <asm/olpc_ofw.h>
  
-#ifdef CONFIG_OPEN_FIRMWARE
-#include <asm/ofw.h>
-#endif
-
 struct olpc_platform_t olpc_platform_info;
 EXPORT_SYMBOL_GPL(olpc_platform_info);
  
  
  
@@ -188,14 +185,15 @@
 }
 EXPORT_SYMBOL_GPL(olpc_ec_cmd);
  
-#ifdef CONFIG_OPEN_FIRMWARE
+#ifdef CONFIG_OLPC_OPENFIRMWARE
 static void __init platform_detect(void)
 {
 	size_t propsize;
 	__be32 rev;
+	void *args[] = { NULL, "board-revision-int", &rev, (void *)4 };
+	void *res[] = { &propsize };
  
-	if (ofw("getprop", 4, 1, NULL, "board-revision-int", &rev, 4,
-			&propsize) || propsize != 4) {
+	if (olpc_ofw("getprop", args, res) || propsize != 4) {
 		printk(KERN_ERR "ofw: getprop call failed!\n");
 		rev = cpu_to_be32(0);
 	}
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <asm/page.h>
+#include <asm/setup.h>
+#include <asm/io.h>
+#include <asm/pgtable.h>
+#include <asm/olpc_ofw.h>
+
+/* address of OFW callback interface; will be NULL if OFW isn't found */
+static int (*olpc_ofw_cif)(int *);
+
+/* page dir entry containing OFW's pgdir table; filled in by head_32.S */
+u32 olpc_ofw_pgd __initdata;
+
+static DEFINE_SPINLOCK(ofw_lock);
+
+#define MAXARGS 10
+
+void __init setup_olpc_ofw_pgd(void)
+{
+	pgd_t *base, *ofw_pde;
+
+	if (!olpc_ofw_cif)
+		return;
+
+	/* fetch OFW's PDE */
+	base = early_ioremap(olpc_ofw_pgd, sizeof(olpc_ofw_pgd) * PTRS_PER_PGD);
+	if (!base) {
+		printk(KERN_ERR "failed to remap OFW's pgd - disabling OFW!\n");
+		olpc_ofw_cif = NULL;
+		return;
+	}
+	ofw_pde = &base[OLPC_OFW_PDE_NR];
+
+	/* install OFW's PDE permanently into the kernel's pgtable */
+	set_pgd(&swapper_pg_dir[OLPC_OFW_PDE_NR], *ofw_pde);
+	early_iounmap(base, sizeof(olpc_ofw_pgd) * PTRS_PER_PGD);
+}
+
+int __olpc_ofw(const char *name, int nr_args, void **args, int nr_res,
+		void **res)
+{
+	int ofw_args[MAXARGS + 3];
+	unsigned long flags;
+	int ret, i, *p;
+
+	BUG_ON(nr_args + nr_res > MAXARGS);
+
+	if (!olpc_ofw_cif)
+		return -EIO;
+
+	ofw_args[0] = (int)name;
+	ofw_args[1] = nr_args;
+	ofw_args[2] = nr_res;
+
+	p = &ofw_args[3];
+	for (i = 0; i < nr_args; i++, p++)
+		*p = (int)args[i];
+
+	/* call into ofw */
+	spin_lock_irqsave(&ofw_lock, flags);
+	ret = olpc_ofw_cif(ofw_args);
+	spin_unlock_irqrestore(&ofw_lock, flags);
+
+	if (!ret) {
+		for (i = 0; i < nr_res; i++, p++)
+			*((int *)res[i]) = *p;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__olpc_ofw);
+
+/* OFW cif _should_ be above this address */
+#define OFW_MIN 0xff000000
+
+/* OFW starts on a 1MB boundary */
+#define OFW_BOUND (1<<20)
+
+void __init olpc_ofw_detect(void)
+{
+	struct olpc_ofw_header *hdr = &boot_params.olpc_ofw_header;
+	unsigned long start;
+
+	/* ensure OFW booted us by checking for "OFW " string */
+	if (hdr->ofw_magic != OLPC_OFW_SIG)
+		return;
+
+	olpc_ofw_cif = (int (*)(int *))hdr->cif_handler;
+
+	if ((unsigned long)olpc_ofw_cif < OFW_MIN) {
+		printk(KERN_ERR "OFW detected, but cif has invalid address 0x%lx - disabling.\n",
+				(unsigned long)olpc_ofw_cif);
+		olpc_ofw_cif = NULL;
+		return;
+	}
+
+	/* determine where OFW starts in memory */
+	start = round_down((unsigned long)olpc_ofw_cif, OFW_BOUND);
+	printk(KERN_INFO "OFW detected in memory, cif @ 0x%lx (reserving top %ldMB)\n",
+			(unsigned long)olpc_ofw_cif, (-start) >> 20);
+	reserve_top_address(-start);
+}
@@ -102,6 +102,7 @@
  
 #include <asm/paravirt.h>
 #include <asm/hypervisor.h>
+#include <asm/olpc_ofw.h>
  
 #include <asm/percpu.h>
 #include <asm/topology.h>
  
@@ -736,9 +737,14 @@
 	/* VMI may relocate the fixmap; do this before touching ioremap area */
 	vmi_init();
  
+	/* OFW also may relocate the fixmap */
+	olpc_ofw_detect();
+
 	early_trap_init();
 	early_cpu_init();
 	early_ioremap_init();
+
+	setup_olpc_ofw_pgd();
  
 	ROOT_DEV = old_decode_dev(boot_params.hdr.root_dev);
 	screen_info = boot_params.screen_info;
...	...	@@ -18,6 +18,7 @@
18	18	080/010 ALL hd0_info hd0 disk parameter, OBSOLETE!!
19	19	090/010 ALL hd1_info hd1 disk parameter, OBSOLETE!!
20	20	0A0/010 ALL sys_desc_table System description table (struct sys_desc_table)
	21	+0B0/010 ALL olpc_ofw_header OLPC's OpenFirmware CIF and friends
21	22	140/080 ALL edid_info Video mode setup (struct edid_info)
22	23	1C0/020 ALL efi_info EFI 32 information (struct efi_info)
23	24	1E0/004 ALL alk_mem_k Alternative mem check, in KB
...	...	@@ -2062,6 +2062,15 @@
2062	2062	Add support for detecting the unique features of the OLPC
2063	2063	XO hardware.
2064	2064
	2065	+config OLPC_OPENFIRMWARE
	2066	+ bool "Support for OLPC's Open Firmware"
	2067	+ depends on !X86_64 && !X86_PAE
	2068	+ default y if OLPC
	2069	+ help
	2070	+ This option adds support for the implementation of Open Firmware
	2071	+ that is used on the OLPC XO-1 Children's Machine.
	2072	+ If unsure, say N here.
	2073	+
2065	2074	endif # X86_32
2066	2075
2067	2076	config K8_NB
...	...	@@ -70,6 +70,14 @@
70	70	__u8 table[14];
71	71	};
72	72
	73	+/* Gleaned from OFW's set-parameters in cpu/x86/pc/linux.fth */
	74	+struct olpc_ofw_header {
	75	+ __u32 ofw_magic; /* OFW signature */
	76	+ __u32 ofw_version;
	77	+ __u32 cif_handler; /* callback into OFW */
	78	+ __u32 irq_desc_table;
	79	+} __attribute__((packed));
	80	+
73	81	struct efi_info {
74	82	__u32 efi_loader_signature;
75	83	__u32 efi_systab;
...	...	@@ -92,7 +100,8 @@
92	100	__u8 hd0_info[16]; /* obsolete! / / 0x080 */
93	101	__u8 hd1_info[16]; /* obsolete! / / 0x090 */
94	102	struct sys_desc_table sys_desc_table; /* 0x0a0 */
95		- __u8 _pad4[144]; /* 0x0b0 */
	103	+ struct olpc_ofw_header olpc_ofw_header; /* 0x0b0 */
	104	+ __u8 _pad4[128]; /* 0x0c0 */
96	105	struct edid_info edid_info; /* 0x140 */
97	106	struct efi_info efi_info; /* 0x1c0 */
98	107	__u32 alt_mem_k; /* 0x1e0 */
	1	+#ifndef _ASM_X86_OLPC_OFW_H
	2	+#define _ASM_X86_OLPC_OFW_H
	3	+
	4	+/* index into the page table containing the entry OFW occupies */
	5	+#define OLPC_OFW_PDE_NR 1022
	6	+
	7	+#define OLPC_OFW_SIG 0x2057464F /* aka "OFW " */
	8	+
	9	+#ifdef CONFIG_OLPC_OPENFIRMWARE
	10	+
	11	+/* run an OFW command by calling into the firmware */
	12	+#define olpc_ofw(name, args, res) \
	13	+ __olpc_ofw((name), ARRAY_SIZE(args), args, ARRAY_SIZE(res), res)
	14	+
	15	+extern int __olpc_ofw(const char name, int nr_args, void *args, int nr_res,
	16	+ void **res);
	17	+
	18	+/* determine whether OFW is available and lives in the proper memory */
	19	+extern void olpc_ofw_detect(void);
	20	+
	21	+/* install OFW's pde permanently into the kernel's pgtable */
	22	+extern void setup_olpc_ofw_pgd(void);
	23	+
	24	+#else /* !CONFIG_OLPC_OPENFIRMWARE */
	25	+
	26	+static inline void olpc_ofw_detect(void) { }
	27	+static inline void setup_olpc_ofw_pgd(void) { }
	28	+
	29	+#endif /* !CONFIG_OLPC_OPENFIRMWARE */
	30	+
	31	+#endif /* _ASM_X86_OLPC_OFW_H */
...	...	@@ -104,6 +104,7 @@
104	104	scx200-y += scx200_32.o
105	105
106	106	obj-$(CONFIG_OLPC) += olpc.o
	107	+obj-$(CONFIG_OLPC_OPENFIRMWARE) += olpc_ofw.o
107	108	obj-$(CONFIG_X86_MRST) += mrst.o
108	109
109	110	microcode-y := microcode_core.o
...	...	@@ -131,6 +131,12 @@
131	131	movsl
132	132	1:
133	133
	134	+#ifdef CONFIG_OLPC_OPENFIRMWARE
	135	+ /* save OFW's pgdir table for later use when calling into OFW */
	136	+ movl %cr3, %eax
	137	+ movl %eax, pa(olpc_ofw_pgd)
	138	+#endif
	139	+
134	140	#ifdef CONFIG_PARAVIRT
135	141	/* This is can only trip for a broken bootloader... */
136	142	cmpw $0x207, pa(boot_params + BP_version)
...	...	@@ -21,11 +21,8 @@
21	21	#include <asm/geode.h>
22	22	#include <asm/setup.h>
23	23	#include <asm/olpc.h>
	24	+#include <asm/olpc_ofw.h>
24	25
25		-#ifdef CONFIG_OPEN_FIRMWARE
26		-#include <asm/ofw.h>
27		-#endif
28		-
29	26	struct olpc_platform_t olpc_platform_info;
30	27	EXPORT_SYMBOL_GPL(olpc_platform_info);
31	28
32	29
33	30
...	...	@@ -188,14 +185,15 @@
188	185	}
189	186	EXPORT_SYMBOL_GPL(olpc_ec_cmd);
190	187
191		-#ifdef CONFIG_OPEN_FIRMWARE
	188	+#ifdef CONFIG_OLPC_OPENFIRMWARE
192	189	static void __init platform_detect(void)
193	190	{
194	191	size_t propsize;
195	192	__be32 rev;
	193	+ void args[] = { NULL, "board-revision-int", &rev, (void )4 };
	194	+ void *res[] = { &propsize };
196	195
197		- if (ofw("getprop", 4, 1, NULL, "board-revision-int", &rev, 4,
198		- &propsize) \|\| propsize != 4) {
	196	+ if (olpc_ofw("getprop", args, res) \|\| propsize != 4) {
199	197	printk(KERN_ERR "ofw: getprop call failed!\n");
200	198	rev = cpu_to_be32(0);
201	199	}
	1	+#include <linux/kernel.h>
	2	+#include <linux/module.h>
	3	+#include <linux/init.h>
	4	+#include <asm/page.h>
	5	+#include <asm/setup.h>
	6	+#include <asm/io.h>
	7	+#include <asm/pgtable.h>
	8	+#include <asm/olpc_ofw.h>
	9	+
	10	+/* address of OFW callback interface; will be NULL if OFW isn't found */
	11	+static int (olpc_ofw_cif)(int );
	12	+
	13	+/* page dir entry containing OFW's pgdir table; filled in by head_32.S */
	14	+u32 olpc_ofw_pgd __initdata;
	15	+
	16	+static DEFINE_SPINLOCK(ofw_lock);
	17	+
	18	+#define MAXARGS 10
	19	+
	20	+void __init setup_olpc_ofw_pgd(void)
	21	+{
	22	+ pgd_t base, ofw_pde;
	23	+
	24	+ if (!olpc_ofw_cif)
	25	+ return;
	26	+
	27	+ /* fetch OFW's PDE */
	28	+ base = early_ioremap(olpc_ofw_pgd, sizeof(olpc_ofw_pgd) * PTRS_PER_PGD);
	29	+ if (!base) {
	30	+ printk(KERN_ERR "failed to remap OFW's pgd - disabling OFW!\n");
	31	+ olpc_ofw_cif = NULL;
	32	+ return;
	33	+ }
	34	+ ofw_pde = &base[OLPC_OFW_PDE_NR];
	35	+
	36	+ /* install OFW's PDE permanently into the kernel's pgtable */
	37	+ set_pgd(&swapper_pg_dir[OLPC_OFW_PDE_NR], *ofw_pde);
	38	+ early_iounmap(base, sizeof(olpc_ofw_pgd) * PTRS_PER_PGD);
	39	+}
	40	+
	41	+int __olpc_ofw(const char name, int nr_args, void *args, int nr_res,
	42	+ void **res)
	43	+{
	44	+ int ofw_args[MAXARGS + 3];
	45	+ unsigned long flags;
	46	+ int ret, i, *p;
	47	+
	48	+ BUG_ON(nr_args + nr_res > MAXARGS);
	49	+
	50	+ if (!olpc_ofw_cif)
	51	+ return -EIO;
	52	+
	53	+ ofw_args[0] = (int)name;
	54	+ ofw_args[1] = nr_args;
	55	+ ofw_args[2] = nr_res;
	56	+
	57	+ p = &ofw_args[3];
	58	+ for (i = 0; i < nr_args; i++, p++)
	59	+ *p = (int)args[i];
	60	+
	61	+ /* call into ofw */
	62	+ spin_lock_irqsave(&ofw_lock, flags);
	63	+ ret = olpc_ofw_cif(ofw_args);
	64	+ spin_unlock_irqrestore(&ofw_lock, flags);
	65	+
	66	+ if (!ret) {
	67	+ for (i = 0; i < nr_res; i++, p++)
	68	+ ((int )res[i]) = *p;
	69	+ }
	70	+
	71	+ return ret;
	72	+}
	73	+EXPORT_SYMBOL_GPL(__olpc_ofw);
	74	+
	75	+/* OFW cif _should_ be above this address */
	76	+#define OFW_MIN 0xff000000
	77	+
	78	+/* OFW starts on a 1MB boundary */
	79	+#define OFW_BOUND (1<<20)
	80	+
	81	+void __init olpc_ofw_detect(void)
	82	+{
	83	+ struct olpc_ofw_header *hdr = &boot_params.olpc_ofw_header;
	84	+ unsigned long start;
	85	+
	86	+ /* ensure OFW booted us by checking for "OFW " string */
	87	+ if (hdr->ofw_magic != OLPC_OFW_SIG)
	88	+ return;
	89	+
	90	+ olpc_ofw_cif = (int ()(int ))hdr->cif_handler;
	91	+
	92	+ if ((unsigned long)olpc_ofw_cif < OFW_MIN) {
	93	+ printk(KERN_ERR "OFW detected, but cif has invalid address 0x%lx - disabling.\n",
	94	+ (unsigned long)olpc_ofw_cif);
	95	+ olpc_ofw_cif = NULL;
	96	+ return;
	97	+ }
	98	+
	99	+ /* determine where OFW starts in memory */
	100	+ start = round_down((unsigned long)olpc_ofw_cif, OFW_BOUND);
	101	+ printk(KERN_INFO "OFW detected in memory, cif @ 0x%lx (reserving top %ldMB)\n",
	102	+ (unsigned long)olpc_ofw_cif, (-start) >> 20);
	103	+ reserve_top_address(-start);
	104	+}
...	...	@@ -102,6 +102,7 @@
102	102
103	103	#include <asm/paravirt.h>
104	104	#include <asm/hypervisor.h>
	105	+#include <asm/olpc_ofw.h>
105	106
106	107	#include <asm/percpu.h>
107	108	#include <asm/topology.h>
108	109
...	...	@@ -736,9 +737,14 @@
736	737	/* VMI may relocate the fixmap; do this before touching ioremap area */
737	738	vmi_init();
738	739
	740	+ /* OFW also may relocate the fixmap */
	741	+ olpc_ofw_detect();
	742	+
739	743	early_trap_init();
740	744	early_cpu_init();
741	745	early_ioremap_init();
	746	+
	747	+ setup_olpc_ofw_pgd();
742	748
743	749	ROOT_DEV = old_decode_dev(boot_params.hdr.root_dev);
744	750	screen_info = boot_params.screen_info;