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ARM: iop32x: use GENERIC_IRQ_MULTI_HANDLER

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iop32x uses the entry-macro.S file for both the IRQ entry and for
hooking into the arch_ret_to_user code path. This is done because the
cp6 registers have to be enabled before accessing any of the interrupt
controller registers but have to be disabled when running in user space.

There is also a lazy-enable logic in cp6.c, but during a hardirq, we
know it has to be enabled.

Both the cp6-enable code and the code to read the IRQ status can be
lifted into the normal generic_handle_arch_irq() path, but the
cp6-disable code has to remain in the user return code. As nothing
other than iop32x uses this hook, just open-code it there with an
ifdef for the platform that can eventually be removed when iop32x
has reached the end of its life.

The cp6-enable path in the IRQ entry has an extra cp_wait barrier that
the trap version does not have, but it is harmless to do it in both
cases to simplify the logic here at the cost of a few extra cycles
for the trap.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
This commit is contained in:
Arnd Bergmann 2021-11-30 11:21:49 +01:00 committed by Ard Biesheuvel
parent 9d67412f24
commit 6f5d248d05
6 changed files with 43 additions and 43 deletions
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5
arch/arm/Kconfig
View file

@ -227,9 +227,6 @@ config GENERIC_ISA_DMA
config FIQ
bool
config NEED_RET_TO_USER
bool
config ARCH_MTD_XIP
bool
@ -371,9 +368,9 @@ config ARCH_IOP32X
bool "IOP32x-based"
depends on MMU
select CPU_XSCALE
select GENERIC_IRQ_MULTI_HANDLER
select GPIO_IOP
select GPIOLIB
select NEED_RET_TO_USER
select FORCE_PCI
select PLAT_IOP
help

16
arch/arm/kernel/entry-common.S
View file

@ -16,12 +16,14 @@
.equ NR_syscalls, __NR_syscalls
#ifdef CONFIG_NEED_RET_TO_USER
#include <mach/entry-macro.S>
#else
.macro arch_ret_to_user, tmp1, tmp2
.endm
.macro arch_ret_to_user, tmp
#ifdef CONFIG_ARCH_IOP32X
mrc p15, 0, \tmp, c15, c1, 0
tst \tmp, #(1 << 6)
bicne \tmp, \tmp, #(1 << 6)
mcrne p15, 0, \tmp, c15, c1, 0 @ Disable cp6 access
#endif
.endm
#include "entry-header.S"
@ -55,7 +57,7 @@ __ret_fast_syscall:
/* perform architecture specific actions before user return */
arch_ret_to_user r1, lr
arch_ret_to_user r1
restore_user_regs fast = 1, offset = S_OFF
UNWIND(.fnend )
@ -128,7 +130,7 @@ no_work_pending:
asm_trace_hardirqs_on save = 0
/* perform architecture specific actions before user return */
arch_ret_to_user r1, lr
arch_ret_to_user r1
ct_user_enter save = 0
restore_user_regs fast = 0, offset = 0

10
arch/arm/mach-iop32x/cp6.c
View file

@ -7,7 +7,7 @@
#include <asm/traps.h>
#include <asm/ptrace.h>
static int cp6_trap(struct pt_regs *regs, unsigned int instr)
void iop_enable_cp6(void)
{
u32 temp;
@ -16,7 +16,15 @@ static int cp6_trap(struct pt_regs *regs, unsigned int instr)
"mrc p15, 0, %0, c15, c1, 0\n\t"
"orr %0, %0, #(1 << 6)\n\t"
"mcr p15, 0, %0, c15, c1, 0\n\t"
"mrc p15, 0, %0, c15, c1, 0\n\t"
"mov %0, %0\n\t"
"sub pc, pc, #4 @ cp_wait\n\t"
: "=r"(temp));
}
static int cp6_trap(struct pt_regs *regs, unsigned int instr)
{
iop_enable_cp6();
return 0;
}

31
arch/arm/mach-iop32x/include/mach/entry-macro.S
View file

@ -1,31 +0,0 @@
/*
* arch/arm/mach-iop32x/include/mach/entry-macro.S
*
* Low-level IRQ helper macros for IOP32x-based platforms
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
.macro get_irqnr_preamble, base, tmp
mrc p15, 0, \tmp, c15, c1, 0
orr \tmp, \tmp, #(1 << 6)
mcr p15, 0, \tmp, c15, c1, 0 @ Enable cp6 access
mrc p15, 0, \tmp, c15, c1, 0
mov \tmp, \tmp
sub pc, pc, #4 @ cp_wait
.endm
.macro get_irqnr_and_base, irqnr, irqstat, base, tmp
mrc p6, 0, \irqstat, c8, c0, 0 @ Read IINTSRC
cmp \irqstat, #0
clzne \irqnr, \irqstat
rsbne \irqnr, \irqnr, #32
.endm
.macro arch_ret_to_user, tmp1, tmp2
mrc p15, 0, \tmp1, c15, c1, 0
ands \tmp2, \tmp1, #(1 << 6)
bicne \tmp1, \tmp1, #(1 << 6)
mcrne p15, 0, \tmp1, c15, c1, 0 @ Disable cp6 access
.endm

1
arch/arm/mach-iop32x/iop3xx.h
View file

@ -225,6 +225,7 @@ extern int iop3xx_get_init_atu(void);
#include <linux/reboot.h>
void iop3xx_map_io(void);
void iop_enable_cp6(void);
void iop_init_cp6_handler(void);
void iop_init_time(unsigned long tickrate);
void iop3xx_restart(enum reboot_mode, const char *);

23
arch/arm/mach-iop32x/irq.c
View file

@ -29,6 +29,15 @@ static void intstr_write(u32 val)
asm volatile("mcr p6, 0, %0, c4, c0, 0" : : "r" (val));
}
static u32 iintsrc_read(void)
{
int irq;
asm volatile("mrc p6, 0, %0, c8, c0, 0" : "=r" (irq));
return irq;
}
static void
iop32x_irq_mask(struct irq_data *d)
{
@ -50,11 +59,25 @@ struct irq_chip ext_chip = {
.irq_unmask = iop32x_irq_unmask,
};
void iop_handle_irq(struct pt_regs *regs)
{
u32 mask;
iop_enable_cp6();
do {
mask = iintsrc_read();
if (mask)
generic_handle_irq(fls(mask));
} while (mask);
}
void __init iop32x_init_irq(void)
{
int i;
iop_init_cp6_handler();
set_handle_irq(iop_handle_irq);
intctl_write(0);
intstr_write(0);