Kernel/armv7 - Bugfixes

- Added .usertext for drop function
- Fixed all (maybe) kernel permissions failures
- Saved user SP on task switch
- Fixed clearing VFS handles on MM_Clear, and not copying them in MM_Clone

diff --git a/Kernel/arch/armv7/link.ld b/Kernel/arch/armv7/link.ld
index b1ae295..bf07b4c 100644 (file)
--- a/Kernel/arch/armv7/link.ld
+++ b/Kernel/arch/armv7/link.ld
@@ -1,6 +1,7 @@
 ENTRY (_start)
 
 _kernel_base = 0x80000000;
+_usertext_vbase = 0xFFFFE000;
 
 SECTIONS
 {
@@ -15,6 +16,18 @@ SECTIONS
                *(.text*)
                *(.rodata*)
        }
+                       
+
+       /* HACKS: User accesible .text section */
+       . = ALIGN(0x1000);
+       gUsertextPhysStart = . - _kernel_base;
+       . = _usertext_vbase;
+       .usertext : AT( gUsertextPhysStart )
+       {
+               *(.usertext)
+       }
+       . += gUsertextPhysStart + _kernel_base - _usertext_vbase;
+       
        /* 0x4000 (4 pages) alignment needed for root table */
        .data ALIGN(0x4000) : AT( ADDR(.data) - _kernel_base )
        {

diff --git a/Kernel/arch/armv7/mm_virt.c b/Kernel/arch/armv7/mm_virt.c
index 8689e09..3b4e519 100644 (file)
--- a/Kernel/arch/armv7/mm_virt.c
+++ b/Kernel/arch/armv7/mm_virt.c
@@ -360,7 +360,7 @@ void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
        if( MM_int_GetPageInfo(VAddr, &pi) )
                return ;
        
-       curFlags = MM_GetPhysAddr(VAddr);
+       curFlags = MM_GetFlags(VAddr);
        if( (curFlags & Mask) == Flags )
                return ;
        curFlags &= ~Mask;
@@ -516,10 +516,26 @@ void MM_int_CloneTable(Uint32 *DestEnt, int Table)
                case 3:
                        // Small page
                        // - If full RW
-                       Debug("%p cur[%i] & 0x230 = 0x%x", Table*256*0x1000, i, cur[i] & 0x230);
-                       if( (cur[i] & 0x230) == 0x030 )
-                               cur[i] |= 0x200;        // Set to full RO (Full RO=COW, User RO = RO)
-                       tmp_map[i] = cur[i];
+//                     Debug("%p cur[%i] & 0x230 = 0x%x", Table*256*0x1000, i, cur[i] & 0x230);
+                       if( (cur[i] & 0x230) == 0x010 )
+                       {
+                               void    *dst, *src;
+                               tPAddr  newpage;
+                               newpage = MM_AllocPhys();
+                               src = (void*)( (Table*256+i)*0x1000 );
+                               dst = (void*)MM_MapTemp(newpage);
+//                             Debug("Taking a copy of kernel page %p (%P)", src, cur[i] & ~0xFFF);
+                               memcpy(dst, src, PAGE_SIZE);
+                               MM_FreeTemp( (tVAddr)dst );
+                               tmp_map[i] = newpage | (cur[i] & 0xFFF);
+                       }
+                       else
+                       {
+                               if( (cur[i] & 0x230) == 0x030 )
+                                       cur[i] |= 0x200;        // Set to full RO (Full RO=COW, User RO = RO)
+                               tmp_map[i] = cur[i];
+                               MM_RefPhys( tmp_map[i] & ~0xFFF );
+                       }
                        break;
                }
        }
@@ -638,12 +654,15 @@ tPAddr MM_Clone(void)
 void MM_ClearUser(void)
 {
         int    i, j;
+       const int       user_table_count = USER_STACK_TOP / (256*0x1000);
        Uint32  *cur = (void*)MM_TABLE0USER;
        Uint32  *tab;
        
 //     MM_DumpTables(0, 0x80000000);
 
-       for( i = 0; i < 0x800-4; i ++ )
+       Log("user_table_count = %i (as opposed to %i)", user_table_count, 0x800-4);
+
+       for( i = 0; i < user_table_count; i ++ )
        {
                switch( cur[i] & 3 )
                {
@@ -678,6 +697,9 @@ void MM_ClearUser(void)
                cur[i] = 0;
        }
        
+       // Final block of 4 tables are KStack
+       i = 0x800 - 4;
+       
        // Clear out unused stacks
        {
                register Uint32 __SP asm("sp");
@@ -869,8 +891,8 @@ tVAddr MM_NewUserStack(void)
                }
                MM_SetFlags(addr+ofs, 0, MM_PFLAG_KERNEL);
        }
-       Log("Return %p", addr + ofs);
-       MM_DumpTables(0, 0x80000000);
+//     Log("Return %p", addr + ofs);
+//     MM_DumpTables(0, 0x80000000);
        return addr + ofs;
 }
 
@@ -943,7 +965,6 @@ void MM_PageFault(Uint32 PC, Uint32 Addr, Uint32 DFSR, int bPrefetch)
        // Check for COW
        if( rv == 0 &&  pi.AP == AP_RO_BOTH )
        {
-               Log_Notice("MMVirt", "COW %p caused by %p", Addr, PC);
                pi.AP = AP_RW_BOTH;
                if( MM_GetRefCount(pi.PhysAddr) > 1 )
                {
@@ -961,8 +982,15 @@ void MM_PageFault(Uint32 PC, Uint32 Addr, Uint32 DFSR, int bPrefetch)
                        memcpy( dst, src, PAGE_SIZE );
                        MM_FreeTemp( (tVAddr)dst );
                        
+                       Log_Notice("MMVirt", "COW %p caused by %p, %P duped to %P", Addr, PC,
+                               pi.PhysAddr, newpage);
+
+                       MM_DerefPhys(pi.PhysAddr);
                        pi.PhysAddr = newpage;
                }
+               else {
+                       Log_Notice("MMVirt", "COW %p caused by %p, took last reference to %P", Addr, PC, pi.PhysAddr);
+               }
                // Unset COW
                pi.AP = AP_RW_BOTH;
                MM_int_SetPageInfo(Addr, &pi);

diff --git a/Kernel/arch/armv7/proc.S b/Kernel/arch/armv7/proc.S
index 44ce9ee..4d7c89f 100644 (file)
--- a/Kernel/arch/armv7/proc.S
+++ b/Kernel/arch/armv7/proc.S
@@ -27,14 +27,6 @@ KernelThreadHeader:
        bl Threads_Exit
        b .
 
-.globl Proc_int_DropToUser
-@ R0: User IP
-@ R1: User SP
-Proc_int_DropToUser:
-       cps #16
-       mov sp, r1
-       mov pc, r0
-
 .globl SwitchTask
 @ R0: New stack
 @ R1: Pointer to where to save old stack
@@ -81,19 +73,29 @@ Proc_CloneInt:
        ldr r0, =Proc_CloneInt_new
        pop {r4-r12,pc}
 Proc_CloneInt_new:
-@      cps #18
-               
-@      mov r0, #0
-@      mvn r1, #0
-@      bl MM_DumpTables
-
-@      ldr r0, =csProc_CloneInt_NewTaskMessage
-@      bl Log
-       
-@      cps #19
        mov r0, #0
        pop {r4-r12,pc}
 
+@ R0: New user SP
+@ Return: Old user SP
+.globl Proc_int_SwapUserSP
+Proc_int_SwapUserSP:
+       cps #31 @ Go to system mode
+       mov r1, sp
+       tst r0, r0      @ Only update if non-zero
+       movne sp, r0
+       mov r0, r1
+       cps #19
+       mov pc, lr
+
+.section .usertext, "ax"
+.globl Proc_int_DropToUser
+@ R0: User IP
+@ R1: User SP
+Proc_int_DropToUser:
+       cps #16
+       mov sp, r1
+       mov pc, r0
 
 .section .rodata
 csProc_CloneInt_NewTaskMessage:

diff --git a/Kernel/arch/armv7/proc.c b/Kernel/arch/armv7/proc.c
index 08257d9..605b156 100644 (file)
--- a/Kernel/arch/armv7/proc.c
+++ b/Kernel/arch/armv7/proc.c
@@ -14,6 +14,7 @@ extern tThread        gThreadZero;
 extern void    SwitchTask(Uint32 NewSP, Uint32 *OldSP, Uint32 NewIP, Uint32 *OldIP, Uint32 MemPtr);
 extern void    KernelThreadHeader(void);       // Actually takes args on stack
 extern void    Proc_int_DropToUser(Uint32 IP, Uint32 SP) NORETURN;
+extern Uint32  Proc_int_SwapUserSP(Uint32 NewSP);
 extern Uint32  Proc_CloneInt(Uint32 *SP, Uint32 *MemPtr);
 extern tVAddr  MM_NewKStack(int bGlobal);      // TODO: Move out into a header
 extern tVAddr  MM_NewUserStack(void);
@@ -92,7 +93,12 @@ void Proc_StartUser(Uint Entrypoint, Uint Base, int ArgC, char **ArgV, int DataS
        
        // Drop to user code
        Log_Debug("Proc", "Proc_int_DropToUser(%p, %p)", Entrypoint, usr_sp);
-       Proc_int_DropToUser(Entrypoint, (Uint32)usr_sp);
+
+       // Needed to get around relocation truncation
+       {
+               void    (*drop)(Uint32, Uint32) NORETURN = Proc_int_DropToUser;
+               drop(Entrypoint, (Uint32)usr_sp);
+       }
 }
 
 tTID Proc_Clone(Uint Flags)
@@ -112,6 +118,8 @@ tTID Proc_Clone(Uint Flags)
        
        new->SavedState.IP = pc;
        new->SavedState.SP = sp;
+       new->SavedState.UserSP = Proc_int_SwapUserSP(0);
+       new->SavedState.UserIP = Proc_GetCurThread()->SavedState.UserIP;
        new->MemState.Base = mem;
 
        Threads_AddActive(new);
@@ -197,14 +205,17 @@ void Proc_Reschedule(void)
        if(!next)       next = gpIdleThread;
        if(!next || next == cur)        return;
 
-       Log("Switching to %p (%i %s) IP=%p SP=%p TTBR0=%p",
+       Log("Switching to %p (%i %s) IP=%p SP=%p TTBR0=%p UsrSP=%p",
                next, next->TID, next->ThreadName,
-               next->SavedState.IP, next->SavedState.SP, next->MemState.Base
+               next->SavedState.IP, next->SavedState.SP, next->MemState.Base,
+               next->SavedState.UserSP
                );
        Log("Requested by %p", __builtin_return_address(0));
        
        gpCurrentThread = next;
 
+       cur->SavedState.UserSP = Proc_int_SwapUserSP( next->SavedState.UserSP );
+
        SwitchTask(
                next->SavedState.SP, &cur->SavedState.SP,
                next->SavedState.IP, &cur->SavedState.IP,

diff --git a/Kernel/arch/armv7/start.S b/Kernel/arch/armv7/start.S
index 3c0779f..589ef19 100644 (file)
--- a/Kernel/arch/armv7/start.S
+++ b/Kernel/arch/armv7/start.S
@@ -89,10 +89,10 @@ SVC_Handler:
        ldr r4, =SyscallHandler
        blx r4
        
-       ldr r0, =csSyscallPrintRetAddr
-       ldr r1, [sp,#9*4+5*4]
-       ldr r4, =Log
-       blx r4
+@      ldr r0, =csSyscallPrintRetAddr
+@      ldr r1, [sp,#9*4+5*4]
+@      ldr r4, =Log
+@      blx r4
        
        pop {r2}        @ errno
        pop {r0,r1}     @ Ret/RetHi
@@ -270,7 +270,7 @@ kernel_table1_map:  @ Size = 4KiB
        .rept (0xF00+16)/4
                .long 0
        .endr
-       .long hwmap_table_0 - KERNEL_BASE + (1 << 4) + 3
+       .long hwmap_table_0 - KERNEL_BASE + 0x13
        .rept 0xFF8/4 - (0xF00+16)/4 - 1
                .long 0
        .endr
@@ -295,9 +295,11 @@ kernel_exception_map:
                .long   0
        .endr
        .long 0x212     @ Map first page for exceptions (Kernel RO, Execute)
-       .rept 15
+       .rept 16-1-2
                .long 0
        .endr
+       .long gUsertextPhysStart + 0x22 @ User .text (User RO, Kernel RW, because both is COW)
+       .long 0
        
 .section .padata
 stack: