sys: Add td_kstack_top inline helper function

This function returns a pointer to the top of the kstack.

Reviewed by:	kib, andrew (arm changes)
Sponsored by:	AFRL, DARPA
Pull Request:	https://ron-dev.freebsd.org/FreeBSD/src/pulls/23

sys/amd64/amd64/vm_machdep.c

@@ -377,8 +377,7 @@ cpu_thread_alloc(struct thread *td)
 void
 cpu_thread_new_kstack(struct thread *td)
 {
-	td->td_md.md_stack_base = td->td_kstack +
-	    td->td_kstack_pages * PAGE_SIZE;
+	td->td_md.md_stack_base = td_kstack_top(td);
 	td->td_frame = (struct trapframe *)td->td_md.md_stack_base - 1;
 }
 

sys/amd64/include/stack.h

@@ -13,16 +13,14 @@
 #define GET_STACK_USAGE(total, used) do {				\
 	struct thread	*td = curthread;				\
 	(total) = td->td_kstack_pages * PAGE_SIZE;			\
-	(used) = td->td_kstack + td->td_kstack_pages * PAGE_SIZE -	\
-	    (char *)&td;						\
+	(used) = td_kstack_top(td) - (char *)&td;			\
 } while (0)
 
 static __inline bool
 kstack_contains(struct thread *td, vm_offset_t va, size_t len)
 {
 	return (va >= (vm_offset_t)td->td_kstack && va + len >= va &&
-	    va + len <= (vm_offset_t)td->td_kstack + td->td_kstack_pages *
-	    PAGE_SIZE);
+	    va + len <= (vm_offset_t)td_kstack_top(td));
 }
 #endif	/* _SYS_PROC_H_ */
 

sys/arm/arm/machdep.c

@@ -378,8 +378,7 @@ init_proc0(void *kstack)
 	proc_linkup0(&proc0, &thread0);
 	thread0.td_kstack = kstack;
 	thread0.td_kstack_pages = kstack_pages;
-	thread0.td_pcb = (struct pcb *)(thread0.td_kstack +
-	    thread0.td_kstack_pages * PAGE_SIZE) - 1;
+	thread0.td_pcb = (struct pcb *)td_kstack_top(&thread0) - 1;
 	thread0.td_pcb->pcb_flags = 0;
 	thread0.td_pcb->pcb_fpflags = 0;
 	thread0.td_pcb->pcb_vfpcpu = -1;

sys/arm/arm/vm_machdep.c

@@ -246,8 +246,7 @@ cpu_thread_alloc(struct thread *td)
 void
 cpu_thread_new_kstack(struct thread *td)
 {
-	td->td_pcb = (struct pcb *)(td->td_kstack + td->td_kstack_pages *
-	    PAGE_SIZE) - 1;
+	td->td_pcb = (struct pcb *)td_kstack_top(td) - 1;
 	/*
 	 * Ensure td_frame is aligned to an 8 byte boundary as it will be
 	 * placed into the stack pointer which must be 8 byte aligned in

sys/arm/include/stack.h

@@ -76,8 +76,7 @@ static __inline bool
 kstack_contains(struct thread *td, vm_offset_t va, size_t len)
 {
 	return (va >= (vm_offset_t)td->td_kstack && va + len >= va &&
-	    va + len <= (vm_offset_t)td->td_kstack + td->td_kstack_pages *
-	    PAGE_SIZE - sizeof(struct pcb));
+	    va + len <= (vm_offset_t)td_kstack_top(td) - sizeof(struct pcb));
 }
 #endif	/* _SYS_PROC_H_ */
 

sys/arm64/arm64/machdep.c

@@ -443,8 +443,7 @@ init_proc0(void *kstack)
 #if defined(PERTHREAD_SSP)
 	thread0.td_md.md_canary = boot_canary;
 #endif
-	thread0.td_pcb = (struct pcb *)(thread0.td_kstack +
-	    thread0.td_kstack_pages * PAGE_SIZE) - 1;
+	thread0.td_pcb = (struct pcb *)td_kstack_top(&thread0) - 1;
 	thread0.td_pcb->pcb_flags = 0;
 	thread0.td_pcb->pcb_fpflags = 0;
 	thread0.td_pcb->pcb_fpusaved = &thread0.td_pcb->pcb_fpustate;

sys/arm64/arm64/vm_machdep.c

@@ -266,8 +266,7 @@ cpu_thread_alloc(struct thread *td)
 void
 cpu_thread_new_kstack(struct thread *td)
 {
-	td->td_pcb = (struct pcb *)(td->td_kstack +
-	    td->td_kstack_pages * PAGE_SIZE) - 1;
+	td->td_pcb = (struct pcb *)td_kstack_top(td) - 1;
 	td->td_frame = (struct trapframe *)STACKALIGN(
 	    (struct trapframe *)td->td_pcb - 1);
 }

sys/arm64/include/stack.h

@@ -51,8 +51,7 @@ static __inline bool
 kstack_contains(struct thread *td, vm_offset_t va, size_t len)
 {
 	return (va >= (vm_offset_t)td->td_kstack && va + len >= va &&
-	    va + len <= (vm_offset_t)td->td_kstack + td->td_kstack_pages *
-	    PAGE_SIZE - sizeof(struct pcb));
+	    va + len <= (vm_offset_t)td_kstack_top(td) - sizeof(struct pcb));
 }
 #endif	/* _SYS_PROC_H_ */
 

sys/ddb/db_ps.c

@@ -358,8 +358,7 @@ DB_SHOW_COMMAND(thread, db_show_thread)
 	if (td->td_name[0] != '\0')
 		db_printf(" name: %s\n", td->td_name);
 	db_printf(" pcb: %p\n", td->td_pcb);
-	db_printf(" stack: %p-%p\n", td->td_kstack,
-	    td->td_kstack + td->td_kstack_pages * PAGE_SIZE - 1);
+	db_printf(" stack: %p-%p\n", td->td_kstack, td_kstack_top(td) - 1);
 	db_printf(" flags: %#x ", td->td_flags);
 	db_printf(" pflags: %#x\n", td->td_pflags);
 	db_printf(" state: ");

sys/i386/i386/machdep.c

@@ -1492,8 +1492,8 @@ init386(int first)
 	PCPU_SET(fsgs_gdt, &gdt[GUFS_SEL].sd);
 
 	/* Initialize the tss (except for the final esp0) early for vm86. */
-	common_tss0.tss_esp0 = (vm_offset_t)thread0.td_kstack +
-	    thread0.td_kstack_pages * PAGE_SIZE - VM86_STACK_SPACE;
+	common_tss0.tss_esp0 = (vm_offset_t)td_kstack_top(&thread0) -
+	    VM86_STACK_SPACE;
 	common_tss0.tss_ss0 = GSEL(GDATA_SEL, SEL_KPL);
 	common_tss0.tss_ioopt = sizeof(struct i386tss) << 16;
 	gsel_tss = GSEL(GPROC0_SEL, SEL_KPL);

sys/i386/i386/vm_machdep.c

@@ -89,7 +89,7 @@ get_pcb_user_save_td(struct thread *td)
 {
 	char *p;
 
-	p = td->td_kstack + td->td_kstack_pages * PAGE_SIZE -
+	p = td_kstack_top(td) -
 	    roundup2(cpu_max_ext_state_size, XSAVE_AREA_ALIGN);
 	KASSERT(__is_aligned(p, XSAVE_AREA_ALIGN),
 	    ("Unaligned pcb_user_save area"));
@@ -110,7 +110,7 @@ get_pcb_td(struct thread *td)
 {
 	char *p;
 
-	p = td->td_kstack + td->td_kstack_pages * PAGE_SIZE -
+	p = td_kstack_top(td) -
 	    roundup2(cpu_max_ext_state_size, XSAVE_AREA_ALIGN) -
 	    sizeof(struct pcb);
 	return ((struct pcb *)p);

sys/powerpc/include/stack.h

@@ -46,8 +46,7 @@ static __inline bool
 kstack_contains(struct thread *td, vm_offset_t va, size_t len)
 {
 	return (va >= (vm_offset_t)td->td_kstack && va + len >= va &&
-	    va + len <= (vm_offset_t)td->td_kstack + td->td_kstack_pages *
-	    PAGE_SIZE - sizeof(struct pcb));
+	    va + len <= (vm_offset_t)td_kstack_top(td) - sizeof(struct pcb));
 }
 #endif	/* _SYS_PROC_H_ */
 

sys/powerpc/powerpc/exec_machdep.c

@@ -1087,8 +1087,8 @@ cpu_thread_new_kstack(struct thread *td)
 {
 	struct pcb *pcb;
 
-	pcb = (struct pcb *)__align_down(td->td_kstack + td->td_kstack_pages *
-	    PAGE_SIZE - sizeof(struct pcb), 0x40);
+	pcb = (struct pcb *)__align_down(td_kstack_top(td) - sizeof(struct pcb),
+	    0x40);
 	td->td_pcb = pcb;
 	td->td_frame = (struct trapframe *)pcb - 1;
 }

sys/powerpc/powerpc/machdep.c

@@ -487,8 +487,8 @@ powerpc_init(vm_offset_t fdt, vm_offset_t toc, vm_offset_t ofentry, void *mdp,
 	/*
 	 * Finish setting up thread0.
 	 */
-	thread0.td_pcb = (struct pcb *)__align_down(thread0.td_kstack +
-	    thread0.td_kstack_pages * PAGE_SIZE - sizeof(struct pcb), 16);
+	thread0.td_pcb = (struct pcb *)__align_down(td_kstack_top(&thread0) -
+	    sizeof(struct pcb), 16);
 	bzero((void *)thread0.td_pcb, sizeof(struct pcb));
 	pc->pc_curpcb = thread0.td_pcb;
 

sys/riscv/include/stack.h

@@ -61,8 +61,7 @@ static __inline bool
 kstack_contains(struct thread *td, vm_offset_t va, size_t len)
 {
 	return (va >= (vm_offset_t)td->td_kstack && va + len >= va &&
-	    va + len <= (vm_offset_t)td->td_kstack + td->td_kstack_pages *
-	    PAGE_SIZE - sizeof(struct pcb));
+	    va + len <= (vm_offset_t)td_kstack_top(td) - sizeof(struct pcb));
 }
 #endif	/* _SYS_PROC_H_ */
 

sys/riscv/riscv/machdep.c

@@ -296,8 +296,7 @@ init_proc0(void *kstack)
 	proc_linkup0(&proc0, &thread0);
 	thread0.td_kstack = kstack;
 	thread0.td_kstack_pages = KSTACK_PAGES;
-	thread0.td_pcb = (struct pcb *)(thread0.td_kstack +
-	    thread0.td_kstack_pages * PAGE_SIZE) - 1;
+	thread0.td_pcb = (struct pcb *)td_kstack_top(&thread0) - 1;
 	thread0.td_pcb->pcb_fpflags = 0;
 	thread0.td_frame = &proc0_tf;
 	pcpup->pc_curpcb = thread0.td_pcb;

sys/riscv/riscv/vm_machdep.c

@@ -61,8 +61,7 @@
 void
 cpu_thread_new_kstack(struct thread *td)
 {
-	td->td_pcb = (struct pcb *)(td->td_kstack +
-	    td->td_kstack_pages * PAGE_SIZE) - 1;
+	td->td_pcb = (struct pcb *)td_kstack_top(td) - 1;
 
 	/*
 	 * td->td_frame + TF_SIZE will be the saved kernel stack pointer whilst

sys/sys/proc.h

@@ -1327,6 +1327,12 @@ td_get_sched(struct thread *td)
 	return ((struct td_sched *)&td[1]);
 }
 
+static __inline char *
+td_kstack_top(struct thread *td)
+{
+	return (td->td_kstack + ptoa(td->td_kstack_pages));
+}
+
 static __inline void
 ruxreset(struct rusage_ext *rux)
 {

sys/vm/vm_glue.c

@@ -739,7 +739,7 @@ intr_prof_stack_use(struct thread *td, struct trapframe *frame)
 	if (TRAPF_USERMODE(frame))
 		return;
 
-	stack_top = td->td_kstack + td->td_kstack_pages * PAGE_SIZE;
+	stack_top = td_kstack_top(td);
 	current = (char *)&stack_top;
 
 	/*