[PATCH 11/14] sparc64: remove CONFIG_SET_FS support

Arnd Bergmann
2022-02-14T16:34:49Z

From: Arnd Bergmann <arnd@arndb.de>

sparc64 uses address space identifiers to differentiate between kernel
and user space, using ASI_P for kernel threads but ASI_AIUS for normal
user space, with the option of changing between them.

As nothing really changes the ASI any more, just hardcode ASI_AIUS
everywhere. Kernel threads are not allowed to access __user pointers
anyway.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
arch/sparc/Kconfig | 1 -
arch/sparc/include/asm/processor_64.h | 4 ----
arch/sparc/include/asm/switch_to_64.h | 4 +---
arch/sparc/include/asm/thread_info_64.h | 4 +---
arch/sparc/include/asm/uaccess_64.h | 24 ------------------------
arch/sparc/kernel/process_64.c | 12 ------------
arch/sparc/kernel/traps_64.c | 2 --
arch/sparc/lib/NGmemcpy.S | 3 +--
arch/sparc/mm/init_64.c | 3 ---
9 files changed, 3 insertions(+), 54 deletions(-)

diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 875388835a58..5f08e4d16ad8 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -99,7 +99,6 @@ config SPARC64
select HAVE_SETUP_PER_CPU_AREA
select NEED_PER_CPU_EMBED_FIRST_CHUNK
select NEED_PER_CPU_PAGE_FIRST_CHUNK
- select SET_FS

config ARCH_PROC_KCORE_TEXT
def_bool y
diff --git a/arch/sparc/include/asm/processor_64.h b/arch/sparc/include/asm/processor_64.h
index ae851e8fce4c..89850dff6b03 100644
--- a/arch/sparc/include/asm/processor_64.h
+++ b/arch/sparc/include/asm/processor_64.h
@@ -47,10 +47,6 @@

#ifndef __ASSEMBLY__

-typedef struct {
- unsigned char seg;
-} mm_segment_t;
-
/* The Sparc processor specific thread struct. */
/* XXX This should die, everything can go into thread_info now. */
struct thread_struct {
diff --git a/arch/sparc/include/asm/switch_to_64.h b/arch/sparc/include/asm/switch_to_64.h
index b1d4e2e3210f..14f3c49bfdbc 100644
--- a/arch/sparc/include/asm/switch_to_64.h
+++ b/arch/sparc/include/asm/switch_to_64.h
@@ -20,10 +20,8 @@ do { \
*/
#define switch_to(prev, next, last) \
do { save_and_clear_fpu(); \
- /* If you are tempted to conditionalize the following */ \
- /* so that ASI is only written if it changes, think again. */ \
__asm__ __volatile__("wr %%g0, %0, %%asi" \
- : : "r" (task_thread_info(next)->current_ds));\
+ : : "r" (ASI_AIUS)); \
trap_block[current_thread_info()->cpu].thread = \
task_thread_info(next); \
__asm__ __volatile__( \
diff --git a/arch/sparc/include/asm/thread_info_64.h b/arch/sparc/include/asm/thread_info_64.h
index 8047a9caab2f..1a44372e2bc0 100644
--- a/arch/sparc/include/asm/thread_info_64.h
+++ b/arch/sparc/include/asm/thread_info_64.h
@@ -46,7 +46,7 @@ struct thread_info {
struct pt_regs *kregs;
int preempt_count; /* 0 => preemptable, <0 => BUG */
__u8 new_child;
- __u8 current_ds;
+ __u8 __pad;
__u16 cpu;

unsigned long *utraps;
@@ -81,7 +81,6 @@ struct thread_info {
#define TI_KREGS 0x00000028
#define TI_PRE_COUNT 0x00000030
#define TI_NEW_CHILD 0x00000034
-#define TI_CURRENT_DS 0x00000035
#define TI_CPU 0x00000036
#define TI_UTRAPS 0x00000038
#define TI_REG_WINDOW 0x00000040
@@ -116,7 +115,6 @@ struct thread_info {
#define INIT_THREAD_INFO(tsk) \
{ \
.task = &tsk, \
- .current_ds = ASI_P, \
.preempt_count = INIT_PREEMPT_COUNT, \
.kregs = (struct pt_regs *)(init_stack+THREAD_SIZE)-1 \
}
diff --git a/arch/sparc/include/asm/uaccess_64.h b/arch/sparc/include/asm/uaccess_64.h
index 000bac67cf31..617a462d1f56 100644
--- a/arch/sparc/include/asm/uaccess_64.h
+++ b/arch/sparc/include/asm/uaccess_64.h
@@ -13,24 +13,6 @@

#include <asm/processor.h>

-/*
- * Sparc64 is segmented, though more like the M68K than the I386.
- * We use the secondary ASI to address user memory, which references a
- * completely different VM map, thus there is zero chance of the user
- * doing something queer and tricking us into poking kernel memory.
- *
- * What is left here is basically what is needed for the other parts of
- * the kernel that expect to be able to manipulate, erum, "segments".
- * Or perhaps more properly, permissions.
- *
- * "For historical reasons, these macros are grossly misnamed." -Linus
- */
-
-#define KERNEL_DS ((mm_segment_t) { ASI_P })
-#define USER_DS ((mm_segment_t) { ASI_AIUS }) /* har har har */
-
-#define get_fs() ((mm_segment_t){(current_thread_info()->current_ds)})
-
static inline int __access_ok(const void __user *addr, unsigned long size)
{
return 1;
@@ -38,12 +20,6 @@ static inline int __access_ok(const void __user *addr, unsigned long size)
#define __access_ok __access_ok
#include <asm-generic/access_ok.h>

-#define set_fs(val) \
-do { \
- current_thread_info()->current_ds = (val).seg; \
- __asm__ __volatile__ ("wr %%g0, %0, %%asi" : : "r" ((val).seg)); \
-} while(0)
-
/*
* Test whether a block of memory is a valid user space address.
* Returns 0 if the range is valid, nonzero otherwise.
diff --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c
index f5b2cac8669f..9a2ceb080ac9 100644
--- a/arch/sparc/kernel/process_64.c
+++ b/arch/sparc/kernel/process_64.c
@@ -106,18 +106,13 @@ static void show_regwindow32(struct pt_regs *regs)
{
struct reg_window32 __user *rw;
struct reg_window32 r_w;
- mm_segment_t old_fs;

__asm__ __volatile__ ("flushw");
rw = compat_ptr((unsigned int)regs->u_regs[14]);
- old_fs = get_fs();
- set_fs (USER_DS);
if (copy_from_user (&r_w, rw, sizeof(r_w))) {
- set_fs (old_fs);
return;
}

- set_fs (old_fs);
printk("l0: %08x l1: %08x l2: %08x l3: %08x "
"l4: %08x l5: %08x l6: %08x l7: %08x\n",
r_w.locals[0], r_w.locals[1], r_w.locals[2], r_w.locals[3],
@@ -136,7 +131,6 @@ static void show_regwindow(struct pt_regs *regs)
struct reg_window __user *rw;
struct reg_window *rwk;
struct reg_window r_w;
- mm_segment_t old_fs;

if ((regs->tstate & TSTATE_PRIV) || !(test_thread_flag(TIF_32BIT))) {
__asm__ __volatile__ ("flushw");
@@ -145,14 +139,10 @@ static void show_regwindow(struct pt_regs *regs)
rwk = (struct reg_window *)
(regs->u_regs[14] + STACK_BIAS);
if (!(regs->tstate & TSTATE_PRIV)) {
- old_fs = get_fs();
- set_fs (USER_DS);
if (copy_from_user (&r_w, rw, sizeof(r_w))) {
- set_fs (old_fs);
return;
}
rwk = &r_w;
- set_fs (old_fs);
}
} else {
show_regwindow32(regs);
@@ -598,7 +588,6 @@ int copy_thread(unsigned long clone_flags, unsigned long sp, unsigned long arg,
memset(child_trap_frame, 0, child_stack_sz);
__thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP] =
(current_pt_regs()->tstate + 1) & TSTATE_CWP;
- t->current_ds = ASI_P;
t->kregs->u_regs[UREG_G1] = sp; /* function */
t->kregs->u_regs[UREG_G2] = arg;
return 0;
@@ -613,7 +602,6 @@ int copy_thread(unsigned long clone_flags, unsigned long sp, unsigned long arg,
t->kregs->u_regs[UREG_FP] = sp;
__thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP] =
(regs->tstate + 1) & TSTATE_CWP;
- t->current_ds = ASI_AIUS;
if (sp != regs->u_regs[UREG_FP]) {
unsigned long csp;

diff --git a/arch/sparc/kernel/traps_64.c b/arch/sparc/kernel/traps_64.c
index 21077821f427..5b4de4a89dec 100644
--- a/arch/sparc/kernel/traps_64.c
+++ b/arch/sparc/kernel/traps_64.c
@@ -2857,8 +2857,6 @@ void __init trap_init(void)
TI_PRE_COUNT != offsetof(struct thread_info,
preempt_count) ||
TI_NEW_CHILD != offsetof(struct thread_info, new_child) ||
- TI_CURRENT_DS != offsetof(struct thread_info,
- current_ds) ||
TI_KUNA_REGS != offsetof(struct thread_info,
kern_una_regs) ||
TI_KUNA_INSN != offsetof(struct thread_info,
diff --git a/arch/sparc/lib/NGmemcpy.S b/arch/sparc/lib/NGmemcpy.S
index 8e4d22a6ba0b..ee51c1230689 100644
--- a/arch/sparc/lib/NGmemcpy.S
+++ b/arch/sparc/lib/NGmemcpy.S
@@ -10,8 +10,7 @@
#include <asm/thread_info.h>
#define GLOBAL_SPARE %g7
#define RESTORE_ASI(TMP) \
- ldub [%g6 + TI_CURRENT_DS], TMP; \
- wr TMP, 0x0, %asi;
+ wr %g0, ASI_AIUS, %asi
#else
#define GLOBAL_SPARE %g5
#define RESTORE_ASI(TMP) \
diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
index 1b23639e2fcd..ee08c279d67c 100644
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -709,9 +709,6 @@ static void __init inherit_prom_mappings(void)

void prom_world(int enter)
{
- if (!enter)
- set_fs(get_fs());
-
__asm__ __volatile__("flushw");
}

--
2.29.2