Kernel/x86_64 - Fix MM_AllocDMA to handle NULL PAddr pointer

diff --git a/KernelLand/Kernel/arch/x86_64/desctab.asm b/KernelLand/Kernel/arch/x86_64/desctab.asm
index e833173..e5e3f24 100644 (file)
--- a/KernelLand/Kernel/arch/x86_64/desctab.asm
+++ b/KernelLand/Kernel/arch/x86_64/desctab.asm
@@ -404,7 +404,7 @@ SyscallStub:
        mov [rsp+0x10], rdi     ; Arg1
        mov [rsp+0x18], rsi     ; Arg2
        mov [rsp+0x20], rdx     ; Arg3
-       mov [rsp+0x28], r10     ; Arg4
+       mov [rsp+0x28], r10     ; Arg4 (r10 used in place of rcx)
        mov [rsp+0x30], r8      ; Arg5
        mov [rsp+0x38], r9      ; Arg6
 

diff --git a/KernelLand/Kernel/arch/x86_64/mm_virt.c b/KernelLand/Kernel/arch/x86_64/mm_virt.c
index 3d89ea6..57308d7 100644 (file)
--- a/KernelLand/Kernel/arch/x86_64/mm_virt.c
+++ b/KernelLand/Kernel/arch/x86_64/mm_virt.c
@@ -861,15 +861,16 @@ void *MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
        void    *ret;
        
        // Sanity Check
-       if(MaxBits < 12 || !PhysAddr)   return 0;
+       ASSERTCR(MaxBits, >=, 12, NULL);
        
        // Fast Allocate
        if(Pages == 1 && MaxBits >= PHYS_BITS)
        {
                phys = MM_AllocPhys();
-               *PhysAddr = phys;
                ret = MM_MapHWPages(phys, 1);
                MM_DerefPhys(phys);
+               if(PhysAddr)
+                       *PhysAddr = phys;
                return ret;
        }
        
@@ -880,7 +881,8 @@ void *MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
        
        // Allocated successfully, now map
        ret = MM_MapHWPages(phys, Pages);
-       *PhysAddr = phys;
+       if(PhysAddr)
+               *PhysAddr = phys;
        // MapHWPages references the pages, so deref them back down to 1
        for(;Pages--;phys+=0x1000)
                MM_DerefPhys(phys);
@@ -897,9 +899,8 @@ void *MM_MapTemp(tPAddr PAddr)
 {
        const int max_slots = (MM_TMPMAP_END - MM_TMPMAP_BASE) / PAGE_SIZE;
        tVAddr  ret = MM_TMPMAP_BASE;
-        int    i;
        
-       for( i = 0; i < max_slots; i ++, ret += PAGE_SIZE )
+       for( int i = 0; i < max_slots; i ++, ret += PAGE_SIZE )
        {
                tPAddr  *ent;
                if( MM_GetPageEntryPtr( ret, 0, 1, 0, &ent) < 0 ) {