kernel: facility for user-visible memory

. map all objects named usermapped_*.o with globally visible
	  pages; usermapped_glo_*.o with the VM 'global' bit on, i.e.
	  permanently in tlb (very scarce resource!)
	. added kinfo, machine, kmessages and loadinfo for a start
	. modified log, tty to make use of the shared messages struct

kernel/Makefile

@@ -6,7 +6,7 @@ PROG=	kernel
 .include "arch/${MACHINE_ARCH}/Makefile.inc"
 
 SRCS+=	clock.c cpulocals.c interrupt.c main.c proc.c system.c \
-	table.c utility.c 
+	table.c utility.c usermapped_data.c
 
 LINKERSCRIPT=${.CURDIR}/arch/${MACHINE_ARCH}/kernel.lds
 

kernel/arch/i386/arch_system.c

@@ -182,6 +182,11 @@ void arch_proc_reset(struct proc *pr)
 	pr->p_reg.ds = USER_DS_SELECTOR;
 }
 
+void arch_set_secondary_ipc_return(struct proc *p, u32_t val)
+{
+	p->p_reg.bx = val;
+}
+
 int restore_fpu(struct proc *pr)
 {
 	int failed;

kernel/arch/i386/kernel.lds

@@ -21,8 +21,14 @@ SECTIONS
 
 	. += _kern_offset;
 
+	. = ALIGN(4096); usermapped_start = .;
+	.usermapped_glo : AT(ADDR(.usermapped_glo) - _kern_offset) { usermapped_glo*.o }
+	. = ALIGN(4096); usermapped_nonglo_start = .;
+	.usermapped : AT(ADDR(.usermapped) - _kern_offset) { usermapped_*.o }
+	. = ALIGN(4096); usermapped_end = .;
 	.text             : AT(ADDR(.text) - _kern_offset) { *(.text*) }
 	.data ALIGN(4096) : AT(ADDR(.data) - _kern_offset) { *(.data .rodata* ) }
+	. = ALIGN(4096);
 	.bss ALIGN(4096)  : AT(ADDR(.bss) - _kern_offset) { *(.bss* COMMON)
 		__k_unpaged__kern_size = . - _kern_vir_base;
 		_kern_size = __k_unpaged__kern_size;

kernel/arch/i386/memory.c

@@ -757,10 +757,14 @@ static int oxpcie_mapping_index = -1,
 	lapic_mapping_index = -1,
 	ioapic_first_index = -1,
 	ioapic_last_index = -1,
-	video_mem_mapping_index = -1;
+	video_mem_mapping_index = -1,
+	usermapped_glo_index = -1,
+	usermapped_index = -1, first_um_idx = -1;
 
 extern char *video_mem;
 
+extern char usermapped_start, usermapped_end, usermapped_nonglo_start;
+
 int arch_phys_map(const int index,
 			phys_bytes *addr,
 			phys_bytes *len,
@@ -769,9 +773,19 @@ int arch_phys_map(const int index,
 	static int first = 1;
 	int freeidx = 0;
 	static char *ser_var = NULL;
+	u32_t glo_len = (u32_t) &usermapped_nonglo_start -
+			(u32_t) &usermapped_start;
 
 	if(first) {
 		video_mem_mapping_index = freeidx++;
+		if(glo_len > 0) {
+			usermapped_glo_index = freeidx++;
+		}
+		
+		usermapped_index = freeidx++;
+		first_um_idx = usermapped_index;
+		if(usermapped_glo_index != -1)
+			first_um_idx = usermapped_glo_index;
 
 #ifdef USE_APIC
 		if(lapic_addr)
@@ -798,21 +812,34 @@ int arch_phys_map(const int index,
 		first = 0;
 	}
 
-#ifdef USE_APIC
-	if (index == video_mem_mapping_index) {
+	if(index == usermapped_glo_index) {
+		*addr = vir2phys(&usermapped_start);
+		*len = glo_len;
+		*flags = VMMF_USER | VMMF_GLO;
+		return OK;
+	}
+	else if(index == usermapped_index) {
+		*addr = vir2phys(&usermapped_nonglo_start);
+		*len = (u32_t) &usermapped_end -
+			(u32_t) &usermapped_nonglo_start;
+		*flags = VMMF_USER;
+		return OK;
+	}
+	else if (index == video_mem_mapping_index) {
 		/* map video memory in so we can print panic messages */
 		*addr = MULTIBOOT_VIDEO_BUFFER;
 		*len = I386_PAGE_SIZE;
-		*flags = 0;
+		*flags = VMMF_WRITE;
 		return OK;
 	}
+#ifdef USE_APIC
 	else if (index == lapic_mapping_index) {
 		/* map the local APIC if enabled */
 		if (!lapic_addr)
 			return EINVAL;
 		*addr = lapic_addr;
 		*len = 4 << 10 /* 4kB */;
-		*flags = VMMF_UNCACHED;
+		*flags = VMMF_UNCACHED | VMMF_WRITE;
 		return OK;
 	}
 	else if (ioapic_enabled && index >= ioapic_first_index && index <= ioapic_last_index) {
@@ -820,7 +847,7 @@ int arch_phys_map(const int index,
 		*addr = io_apic[ioapic_idx].paddr;
 		assert(*addr);
 		*len = 4 << 10 /* 4kB */;
-		*flags = VMMF_UNCACHED;
+		*flags = VMMF_UNCACHED | VMMF_WRITE;
 		printf("ioapic map: addr 0x%lx\n", *addr);
 		return OK;
 	}
@@ -830,7 +857,7 @@ int arch_phys_map(const int index,
 	if(index == oxpcie_mapping_index) {
 		*addr = strtoul(ser_var+2, NULL, 16);
 		*len = 0x4000;
-		*flags = VMMF_UNCACHED;
+		*flags = VMMF_UNCACHED | VMMF_WRITE;
 		return OK;
 	}
 #endif
@@ -860,6 +887,31 @@ int arch_phys_map_reply(const int index, const vir_bytes addr)
 		return OK;
 	}
 #endif
+	if(index == first_um_idx) {
+		u32_t usermapped_offset;
+		assert(addr > (u32_t) &usermapped_start);
+		usermapped_offset = addr - (u32_t) &usermapped_start;
+		memset(&minix_kerninfo, 0, sizeof(minix_kerninfo));
+#define FIXEDPTR(ptr) (void *) ((u32_t)ptr + usermapped_offset)
+#define FIXPTR(ptr) ptr = FIXEDPTR(ptr)
+#define ASSIGN(minixstruct) minix_kerninfo.minixstruct = FIXEDPTR(&minixstruct)
+		ASSIGN(kinfo);
+		ASSIGN(machine);
+		ASSIGN(kmessages);
+		ASSIGN(loadinfo);
+
+		/* adjust the pointers of the functions and the struct
+		 * itself to the user-accessible mapping
+		 */
+		minix_kerninfo.kerninfo_magic = KERNINFO_MAGIC;
+		minix_kerninfo.minix_feature_flags = minix_feature_flags;
+		minix_kerninfo_user = (vir_bytes) FIXEDPTR(&minix_kerninfo);
+
+		return OK;
+	}
+
+	if(index == usermapped_index) return OK;
+
 	if (index == video_mem_mapping_index) {
 		video_mem_vaddr =  addr;
 		return OK;

kernel/arch/i386/pre_init.c

@@ -26,7 +26,7 @@
 
 /* to-be-built kinfo struct, diagnostics buffer */
 kinfo_t kinfo;
-struct kmessages kmess;
+struct kmessages kmessages;
 
 /* pg_utils.c uses this; in this phase, there is a 1:1 mapping. */
 phys_bytes vir2phys(void *addr) { return (phys_bytes) addr; } 

kernel/glo.h

@@ -19,11 +19,18 @@
 #include "debug.h"
 
 /* Kernel information structures. This groups vital kernel information. */
-EXTERN struct kinfo kinfo;		/* kernel information for users */
-EXTERN struct machine machine;		/* machine information for users */
-EXTERN struct kmessages kmess;  	/* diagnostic messages in kernel */
-EXTERN struct k_randomness krandom;	/* gather kernel random information */
-EXTERN struct loadinfo kloadinfo;	/* status of load average */
+extern struct kinfo kinfo;		  /* kernel information for users */
+extern struct machine machine;		  /* machine information for users */
+extern struct kmessages kmessages;  	  /* diagnostic messages in kernel */
+extern struct loadinfo loadinfo;	  /* status of load average */
+extern struct minix_kerninfo minix_kerninfo;
+
+EXTERN struct k_randomness krandom; 	/* gather kernel random information */
+
+vir_bytes minix_kerninfo_user;
+
+#define kmess kmessages
+#define kloadinfo loadinfo
 
 /* Process scheduling information and the kernel reentry count. */
 EXTERN struct proc *vmrequest;  /* first process on vmrequest queue */

kernel/proc.c

@@ -608,6 +608,16 @@ int do_ipc(reg_t r1, reg_t r2, reg_t r3)
 	        return EDOM;
   	    return mini_senda(caller_ptr, (asynmsg_t *) r3, msg_size);
   	}
+  	case MINIX_KERNINFO:
+	{
+		/* It might not be initialized yet. */
+	  	if(!minix_kerninfo_user) {
+			return EBADCALL;
+		}
+
+  		arch_set_secondary_ipc_return(caller_ptr, minix_kerninfo_user);
+  		return OK;
+	}
   	default:
 	return EBADCALL;		/* illegal system call */
   }

kernel/proto.h

@@ -150,6 +150,7 @@ void stop_profile_clock(void);
 /* functions defined in architecture-dependent files. */
 void prot_init();
 void arch_post_init();
+void arch_set_secondary_ipc_return(struct proc *, u32_t val);
 phys_bytes phys_copy(phys_bytes source, phys_bytes dest, phys_bytes
 	count);
 void phys_copy_fault(void);

kernel/system/do_getinfo.c

@@ -167,11 +167,6 @@ int do_getinfo(struct proc * caller, message * m_ptr)
 
     	break;
     }
-    case GET_KMESSAGES: {
-        length = sizeof(struct kmessages);
-        src_vir = (vir_bytes) &kmess;
-        break;
-    }
     case GET_IRQACTIDS: {
         length = sizeof(irq_actids);
         src_vir = (vir_bytes) irq_actids;

kernel/usermapped_data.c

@@ -0,0 +1,11 @@
+#include "kernel.h"
+
+/* This is the user-visible struct that has pointers to other bits of data. */
+struct minix_kerninfo minix_kerninfo;
+
+/* Kernel information structures. */
+struct kinfo kinfo;               /* kernel information for users */
+struct machine machine;           /* machine information for users */
+struct kmessages kmessages;       /* diagnostic messages in kernel */
+struct loadinfo loadinfo;        /* status of load average */
+