shithub: riscv

Info  •  Files  •  Log  •  Branches

pc64: get rid of TSTKTOP, USTKTOP is the end of user address space

the temporary stack segment used to be at a fixed address above or
below the user stack. these days, the temp stack is mapped dynamically
by sysexec so TSTKTOP is obsolete.

--- a/sys/src/9/pc64/mem.h

+++ b/sys/src/9/pc64/mem.h

@@ -44,9 +44,8 @@

  */

 #define UTZERO		(0x0000000000200000ull)		/* first address in user text */

 #define UADDRMASK	(0x00007fffffffffffull)		/* canonical address mask */

-#define TSTKTOP		(0x00007ffffffff000ull)

+#define USTKTOP		(0x00007ffffffff000ull)

 #define USTKSIZE	(16*MiB)			/* size of user stack */

-#define USTKTOP		(TSTKTOP-USTKSIZE)		/* end of new stack in sysexec */

 /*

  *  Address spaces. Kernel, sorted by address.

--- a/sys/src/9/pc64/mmu.c

+++ b/sys/src/9/pc64/mmu.c

@@ -221,12 +221,12 @@

 	flags = PTEWRITE|PTEVALID;

 	if(va < VMAP){

 		assert(up != nil);

-		assert((va < TSTKTOP) || (va >= KMAP && va < KMAP+KMAPSIZE));

+		assert((va < USTKTOP) || (va >= KMAP && va < KMAP+KMAPSIZE));

 		p = mmualloc();

 		p->index = index;

 		p->level = level;

-		if(va < TSTKTOP){

+		if(va < USTKTOP){

 			flags |= PTEUSER;

 			if(level == PML4E){

 				if((p->next = up->mmuhead) == nil)

@@ -341,9 +341,9 @@

 	/* common case */

 	pte[PTLX(UTZERO, 3)] = 0;

-	pte[PTLX(TSTKTOP, 3)] = 0;

+	pte[PTLX(USTKTOP-1, 3)] = 0;

 	m->mmumap[PTLX(UTZERO, 3)/MAPBITS] &= ~(1ull<<(PTLX(UTZERO, 3)%MAPBITS));

-	m->mmumap[PTLX(TSTKTOP, 3)/MAPBITS] &= ~(1ull<<(PTLX(TSTKTOP, 3)%MAPBITS));

+	m->mmumap[PTLX(USTKTOP-1, 3)/MAPBITS] &= ~(1ull<<(PTLX(USTKTOP-1, 3)%MAPBITS));

 	for(i = 0; i < nelem(m->mmumap); pte += MAPBITS, i++){

 		if((w = m->mmumap[i]) == 0)