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Date: Tue, 3 Sep 2013 14:45:52 -0400
From: Chris Metcalf <cmetcalf@...era.com>
To: Gleb Natapov <gleb@...hat.com>, <linux-kernel@...r.kernel.org>,
<kvm@...r.kernel.org>, Paolo Bonzini <pbonzini@...hat.com>,
Jan Kiszka <jan.kiszka@...mens.com>
Subject: [PATCH 2/3] tile: don't assume user privilege is zero
Technically, user privilege is anything less than kernel
privilege. We modify the existing user_mode() macro to have
this semantic (and use it in a couple of places it wasn't being
used before), and add an IS_KERNEL_EX1() macro to the assembly
code as well.
Signed-off-by: Chris Metcalf <cmetcalf@...era.com>
---
arch/tile/include/asm/processor.h | 4 ++--
arch/tile/include/asm/ptrace.h | 2 +-
arch/tile/kernel/intvec_64.S | 23 +++++++++++++++++------
arch/tile/kernel/stack.c | 2 +-
arch/tile/mm/fault.c | 4 ++--
5 files changed, 23 insertions(+), 12 deletions(-)
diff --git a/arch/tile/include/asm/processor.h b/arch/tile/include/asm/processor.h
index 230b830..c72fcba 100644
--- a/arch/tile/include/asm/processor.h
+++ b/arch/tile/include/asm/processor.h
@@ -15,6 +15,8 @@
#ifndef _ASM_TILE_PROCESSOR_H
#define _ASM_TILE_PROCESSOR_H
+#include <arch/chip.h>
+
#ifndef __ASSEMBLY__
/*
@@ -25,7 +27,6 @@
#include <asm/ptrace.h>
#include <asm/percpu.h>
-#include <arch/chip.h>
#include <arch/spr_def.h>
struct task_struct;
@@ -347,7 +348,6 @@ extern int kdata_huge;
/*
* Provide symbolic constants for PLs.
- * Note that assembly code assumes that USER_PL is zero.
*/
#define USER_PL 0
#if CONFIG_KERNEL_PL == 2
diff --git a/arch/tile/include/asm/ptrace.h b/arch/tile/include/asm/ptrace.h
index 0d25c21..b9620c0 100644
--- a/arch/tile/include/asm/ptrace.h
+++ b/arch/tile/include/asm/ptrace.h
@@ -39,7 +39,7 @@ typedef unsigned long pt_reg_t;
#define user_stack_pointer(regs) ((regs)->sp)
/* Does the process account for user or for system time? */
-#define user_mode(regs) (EX1_PL((regs)->ex1) == USER_PL)
+#define user_mode(regs) (EX1_PL((regs)->ex1) < KERNEL_PL)
/* Fill in a struct pt_regs with the current kernel registers. */
struct pt_regs *get_pt_regs(struct pt_regs *);
diff --git a/arch/tile/kernel/intvec_64.S b/arch/tile/kernel/intvec_64.S
index 3b35bb4..f020f01 100644
--- a/arch/tile/kernel/intvec_64.S
+++ b/arch/tile/kernel/intvec_64.S
@@ -34,6 +34,16 @@
#define PTREGS_OFFSET_SYSCALL PTREGS_OFFSET_REG(TREG_SYSCALL_NR)
+#if CONFIG_KERNEL_PL == 1 || CONFIG_KERNEL_PL == 2
+/*
+ * Set "result" non-zero if ex1 holds the PL of the kernel
+ * (with or without ICS being set). Note this works only
+ * because we never find the PL at level 3.
+ */
+# define IS_KERNEL_EX1(result, ex1) andi result, ex1, CONFIG_KERNEL_PL
+#else
+# error Recode IS_KERNEL_EX1 for CONFIG_KERNEL_PL
+#endif
.macro push_reg reg, ptr=sp, delta=-8
{
@@ -308,7 +318,7 @@ intvec_\vecname:
*/
{
blbs sp, 2f
- andi r0, r0, SPR_EX_CONTEXT_1_1__PL_MASK /* mask off ICS */
+ IS_KERNEL_EX1(r0, r0)
}
.ifc \vecnum, INT_DOUBLE_FAULT
@@ -641,11 +651,12 @@ intvec_\vecname:
/*
* If we will be returning to the kernel, we will need to
* reset the interrupt masks to the state they had before.
- * Set DISABLE_IRQ in flags iff we came from PL1 with irqs disabled.
+ * Set DISABLE_IRQ in flags iff we came from kernel pl with
+ * irqs disabled.
*/
mfspr r32, SPR_EX_CONTEXT_K_1
{
- andi r32, r32, SPR_EX_CONTEXT_1_1__PL_MASK /* mask off ICS */
+ IS_KERNEL_EX1(r22, r22)
PTREGS_PTR(r21, PTREGS_OFFSET_FLAGS)
}
beqzt r32, 1f /* zero if from user space */
@@ -812,7 +823,7 @@ STD_ENTRY(interrupt_return)
PTREGS_PTR(r29, PTREGS_OFFSET_EX1)
}
ld r29, r29
- andi r29, r29, SPR_EX_CONTEXT_1_1__PL_MASK /* mask off ICS */
+ IS_KERNEL_EX1(r29, r29)
{
beqzt r29, .Lresume_userspace
move r29, sp
@@ -936,7 +947,7 @@ STD_ENTRY(interrupt_return)
PTREGS_PTR(r32, PTREGS_OFFSET_FLAGS)
}
{
- andi r0, r0, SPR_EX_CONTEXT_1_1__PL_MASK
+ IS_KERNEL_EX1(r0, r0)
ld r32, r32
}
bnez r0, 1f
@@ -1007,7 +1018,7 @@ STD_ENTRY(interrupt_return)
pop_reg r21, sp, PTREGS_OFFSET_REG(31) - PTREGS_OFFSET_PC
{
mtspr SPR_EX_CONTEXT_K_1, lr
- andi lr, lr, SPR_EX_CONTEXT_1_1__PL_MASK /* mask off ICS */
+ IS_KERNEL_EX1(lr, lr)
}
{
mtspr SPR_EX_CONTEXT_K_0, r21
diff --git a/arch/tile/kernel/stack.c b/arch/tile/kernel/stack.c
index 24fd223..362284a 100644
--- a/arch/tile/kernel/stack.c
+++ b/arch/tile/kernel/stack.c
@@ -103,7 +103,7 @@ static struct pt_regs *valid_fault_handler(struct KBacktraceIterator* kbt)
p->sp >= sp) {
if (kbt->verbose)
pr_err(" <%s while in kernel mode>\n", fault);
- } else if (EX1_PL(p->ex1) == USER_PL &&
+ } else if (user_mode(p) &&
p->sp < PAGE_OFFSET && p->sp != 0) {
if (kbt->verbose)
pr_err(" <%s while in user mode>\n", fault);
diff --git a/arch/tile/mm/fault.c b/arch/tile/mm/fault.c
index 64eec3f..39c48cb 100644
--- a/arch/tile/mm/fault.c
+++ b/arch/tile/mm/fault.c
@@ -283,7 +283,7 @@ static int handle_page_fault(struct pt_regs *regs,
flags = (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
(write ? FAULT_FLAG_WRITE : 0));
- is_kernel_mode = (EX1_PL(regs->ex1) != USER_PL);
+ is_kernel_mode = !user_mode(regs);
tsk = validate_current();
@@ -824,7 +824,7 @@ void do_page_fault(struct pt_regs *regs, int fault_num,
}
#if CHIP_HAS_TILE_DMA() || CHIP_HAS_SN_PROC()
- if (EX1_PL(regs->ex1) != USER_PL) {
+ if (!user_mode(regs)) {
struct async_tlb *async;
switch (fault_num) {
#if CHIP_HAS_TILE_DMA()
--
1.8.3.1
--
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