[PATCH v3 0/4] add TOC support

[PATCH v3 0/4] add TOC support

[Sven Schnelle]

This adds support for the TOC switches found on most PA-RISC
machines. I tested this on my c8000 and a HP 16702A, which is
basically a B160L with some logic analyzer hardware.

Changes in v3:
- add config option
- move toc code to its own c & .S file
- use early_initcall for setup
- split out struct declarations
- use sizeof(*ret) instead of sizeof(struct x)
- move virt_map to assembly.h so it can be used from other files

Changes in v2:
- fix stack allocation
- align toc_lock on 16 byte boundary
- move toc_lock declaration to processor.c

Sven Schnelle (4):
  parisc: move virt_map macro to assembly.h
  parisc: add PIM TOC data structures
  parisc/firmware: add functions to retrieve TOC data
  parisc: add support for TOC (transfer of control)

 arch/parisc/Kconfig                 |  14 ++++
 arch/parisc/include/asm/assembly.h  |  25 +++++++
 arch/parisc/include/asm/pdc.h       |   2 +
 arch/parisc/include/asm/processor.h |   4 +
 arch/parisc/include/uapi/asm/pdc.h  |  28 ++++++-
 arch/parisc/kernel/Makefile         |   1 +
 arch/parisc/kernel/entry.S          |  24 ------
 arch/parisc/kernel/firmware.c       |  32 ++++++++
 arch/parisc/kernel/toc.c            | 111 ++++++++++++++++++++++++++++
 arch/parisc/kernel/toc_asm.S        |  88 ++++++++++++++++++++++
 10 files changed, 303 insertions(+), 26 deletions(-)
 create mode 100644 arch/parisc/kernel/toc.c
 create mode 100644 arch/parisc/kernel/toc_asm.S

-- 
2.33.0

[PATCH v3 1/4] parisc: move virt_map macro to assembly.h

[Sven Schnelle]

This macro will also be used by the TOC code, so move it
into asm/assembly.h to avoid duplication.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
---
 arch/parisc/include/asm/assembly.h | 25 +++++++++++++++++++++++++
 arch/parisc/kernel/entry.S         | 24 ------------------------
 2 files changed, 25 insertions(+), 24 deletions(-)

diff --git a/arch/parisc/include/asm/assembly.h b/arch/parisc/include/asm/assembly.h
index a39250cb7dfc..d1d16d7b3607 100644
--- a/arch/parisc/include/asm/assembly.h
+++ b/arch/parisc/include/asm/assembly.h
@@ -71,6 +71,7 @@
 #include <asm/types.h>
 
 #include <asm/asmregs.h>
+#include <asm/psw.h>
 
 	sp	=	30
 	gp	=	27
@@ -497,6 +498,30 @@
 	nop	/* 7 */
 	.endm
 
+	/* Switch to virtual mapping, trashing only %r1 */
+	.macro  virt_map
+	/* pcxt_ssm_bug */
+	rsm	PSW_SM_I, %r0		/* barrier for "Relied upon Translation */
+	mtsp	%r0, %sr4
+	mtsp	%r0, %sr5
+	mtsp	%r0, %sr6
+	tovirt_r1 %r29
+	load32	KERNEL_PSW, %r1
+
+	rsm     PSW_SM_QUIET,%r0	/* second "heavy weight" ctl op */
+	mtctl	%r0, %cr17		/* Clear IIASQ tail */
+	mtctl	%r0, %cr17		/* Clear IIASQ head */
+	mtctl	%r1, %ipsw
+	load32	4f, %r1
+	mtctl	%r1, %cr18		/* Set IIAOQ tail */
+	ldo	4(%r1), %r1
+	mtctl	%r1, %cr18		/* Set IIAOQ head */
+	rfir
+	nop
+4:
+	.endm
+
+
 	/*
 	 * ASM_EXCEPTIONTABLE_ENTRY
 	 *
diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
index 9f939afe6b88..91e0540e5213 100644
--- a/arch/parisc/kernel/entry.S
+++ b/arch/parisc/kernel/entry.S
@@ -51,30 +51,6 @@
 	extrd,u \spc,(64 - (SPACEID_SHIFT)),32,\prot
 	.endm
 #endif
-
-	/* Switch to virtual mapping, trashing only %r1 */
-	.macro  virt_map
-	/* pcxt_ssm_bug */
-	rsm	PSW_SM_I, %r0	/* barrier for "Relied upon Translation */
-	mtsp	%r0, %sr4
-	mtsp	%r0, %sr5
-	mtsp	%r0, %sr6
-	tovirt_r1 %r29
-	load32	KERNEL_PSW, %r1
-
-	rsm     PSW_SM_QUIET,%r0	/* second "heavy weight" ctl op */
-	mtctl	%r0, %cr17	/* Clear IIASQ tail */
-	mtctl	%r0, %cr17	/* Clear IIASQ head */
-	mtctl	%r1, %ipsw
-	load32	4f, %r1
-	mtctl	%r1, %cr18	/* Set IIAOQ tail */
-	ldo	4(%r1), %r1
-	mtctl	%r1, %cr18	/* Set IIAOQ head */
-	rfir
-	nop
-4:
-	.endm
-
 	/*
 	 * The "get_stack" macros are responsible for determining the
 	 * kernel stack value.
-- 
2.33.0

[PATCH v3 2/4] parisc: add PIM TOC data structures

[Sven Schnelle]

These data structures describe the TOC data we get from firmware
when issuing a PDC_PIM_TOC request.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
---
 arch/parisc/include/uapi/asm/pdc.h | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/arch/parisc/include/uapi/asm/pdc.h b/arch/parisc/include/uapi/asm/pdc.h
index 15211723ebf5..ad51df8ba952 100644
--- a/arch/parisc/include/uapi/asm/pdc.h
+++ b/arch/parisc/include/uapi/asm/pdc.h
@@ -689,6 +689,28 @@ struct pdc_hpmc_pim_20 { /* PDC_PIM */
 	unsigned long long fr[32];
 };
 
+struct pdc_toc_pim_11 {
+	unsigned int gr[32];
+	unsigned int cr[32];
+	unsigned int sr[8];
+	unsigned int iasq_back;
+	unsigned int iaoq_back;
+	unsigned int check_type;
+	unsigned int hversion;
+	unsigned int cpu_state;
+};
+
+struct pdc_toc_pim_20 {
+	unsigned long long gr[32];
+	unsigned long long cr[32];
+	unsigned long long sr[8];
+	unsigned long long iasq_back;
+	unsigned long long iaoq_back;
+	unsigned int check_type;
+	unsigned int hversion;
+	unsigned int cpu_state;
+};
+
 #endif /* !defined(__ASSEMBLY__) */
 
 #endif /* _UAPI_PARISC_PDC_H */
-- 
2.33.0

[PATCH v3 3/4] parisc/firmware: add functions to retrieve TOC data

[Sven Schnelle]

Add functions to retrieve TOC data from firmware both
for 1.1 and 2.0 PDC.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
---
 arch/parisc/include/asm/pdc.h |  2 ++
 arch/parisc/kernel/firmware.c | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/arch/parisc/include/asm/pdc.h b/arch/parisc/include/asm/pdc.h
index b388d8176588..18b957a8630d 100644
--- a/arch/parisc/include/asm/pdc.h
+++ b/arch/parisc/include/asm/pdc.h
@@ -51,6 +51,8 @@ int pdc_spaceid_bits(unsigned long *space_bits);
 int pdc_btlb_info(struct pdc_btlb_info *btlb);
 int pdc_mem_map_hpa(struct pdc_memory_map *r_addr, struct pdc_module_path *mod_path);
 #endif /* !CONFIG_PA20 */
+int pdc_pim_toc11(struct pdc_toc_pim_11 *ret);
+int pdc_pim_toc20(struct pdc_toc_pim_20 *ret);
 int pdc_lan_station_id(char *lan_addr, unsigned long net_hpa);
 
 int pdc_stable_read(unsigned long staddr, void *memaddr, unsigned long count);
diff --git a/arch/parisc/kernel/firmware.c b/arch/parisc/kernel/firmware.c
index 7034227dbdf3..3370e347dde3 100644
--- a/arch/parisc/kernel/firmware.c
+++ b/arch/parisc/kernel/firmware.c
@@ -1061,6 +1061,38 @@ int pdc_mem_pdt_read_entries(struct pdc_mem_read_pdt *pret,
 	return retval;
 }
 
+/**
+ * pdc_pim_toc11 - Fetch TOC PIM 1.1 data from firmware.
+ * @ret: pointer to return buffer
+ */
+int pdc_pim_toc11(struct pdc_toc_pim_11 *ret)
+{
+	int retval;
+	unsigned long flags;
+
+	spin_lock_irqsave(&pdc_lock, flags);
+	retval = mem_pdc_call(PDC_PIM, PDC_PIM_TOC, __pa(pdc_result),
+			      __pa(ret), sizeof(*ret));
+	spin_unlock_irqrestore(&pdc_lock, flags);
+	return retval;
+}
+
+/**
+ * pdc_pim_toc20 - Fetch TOC PIM 2.0 data from firmware.
+ * @ret: pointer to return buffer
+ */
+int pdc_pim_toc20(struct pdc_toc_pim_20 *ret)
+{
+	int retval;
+	unsigned long flags;
+
+	spin_lock_irqsave(&pdc_lock, flags);
+	retval = mem_pdc_call(PDC_PIM, PDC_PIM_TOC, __pa(pdc_result),
+			      __pa(ret), sizeof(*ret));
+	spin_unlock_irqrestore(&pdc_lock, flags);
+	return retval;
+}
+
 /**
  * pdc_tod_set - Set the Time-Of-Day clock.
  * @sec: The number of seconds since epoch.
-- 
2.33.0

[PATCH v3 4/4] parisc: add support for TOC (transfer of control)

[Sven Schnelle]

Almost all PA-RISC machines have either a button that
is labeled with 'TOC' or a BMC function to trigger a TOC.
TOC is a non-maskable interrupt that is sent to the processor.
This can be used for diagnostic purposes like obtaining a
stack trace/register dump or to enter KDB/KGDB.

As an example, on my c8000, TOC can be used with:

CONFIG_KGDB=y
CONFIG_KGDB_KDB=y

and the 'kgdboc=ttyS0,115200' appended to the command line.

Press ^[( on serial console, which will enter the BMC command line,
and enter 'TOC s':

root@(none):/# (
cli>TOC s
Sending TOC/INIT.
<Cpu3> 2800035d03e00000  0000000040c21ac8  CC_ERR_CHECK_TOC
<Cpu0> 2800035d00e00000  0000000040c21ad0  CC_ERR_CHECK_TOC
<Cpu2> 2800035d02e00000  0000000040c21ac8  CC_ERR_CHECK_TOC
<Cpu1> 2800035d01e00000  0000000040c21ad0  CC_ERR_CHECK_TOC
<Cpu3> 37000f7303e00000  2000000000000000  CC_ERR_CPU_CHECK_SUMMARY
<Cpu0> 37000f7300e00000  2000000000000000  CC_ERR_CPU_CHECK_SUMMARY
<Cpu2> 37000f7302e00000  2000000000000000  CC_ERR_CPU_CHECK_SUMMARY
<Cpu1> 37000f7301e00000  2000000000000000  CC_ERR_CPU_CHECK_SUMMARY
<Cpu3> 4300100803e00000  c0000000001d26cc  CC_MC_BR_TO_OS_TOC
<Cpu0> 4300100800e00000  c0000000001d26cc  CC_MC_BR_TO_OS_TOC
<Cpu2> 4300100802e00000  c0000000001d26cc  CC_MC_BR_TO_OS_TOC
<Cpu1> 4300100801e00000  c0000000001d26cc  CC_MC_BR_TO_OS_TOC

Entering kdb (current=0x00000000411cef80, pid 0) on processor 0 due to NonMaskable Interrupt @ 0x40c21ad0
[0]kdb>

Signed-off-by: Sven Schnelle <svens@stackframe.org>
---
 arch/parisc/Kconfig                 |  14 ++++
 arch/parisc/include/asm/processor.h |   4 +
 arch/parisc/include/uapi/asm/pdc.h  |   6 +-
 arch/parisc/kernel/Makefile         |   1 +
 arch/parisc/kernel/toc.c            | 111 ++++++++++++++++++++++++++++
 arch/parisc/kernel/toc_asm.S        |  88 ++++++++++++++++++++++
 6 files changed, 222 insertions(+), 2 deletions(-)
 create mode 100644 arch/parisc/kernel/toc.c
 create mode 100644 arch/parisc/kernel/toc_asm.S

diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index 27a8b49af11f..97a889eaffe1 100644
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -288,6 +288,20 @@ config SMP
 
 	  If you don't know what to do here, say N.
 
+config TOC
+	bool "Support TOC switch"
+	default y if 64BIT || !SMP
+	help
+	  Most PA-RISC machines have either a switch at the back of the machine
+	  or a command in BMC to trigger a TOC interrupt. If you say Y here a
+	  handler will be installed which will either show a backtrace on all
+	  CPUs, or enter a possible configured debugger like kgdb/kdb.
+
+	  Note that with this option enabled, the kernel will use an additional 16KB
+	  per possible CPU as a special stack for the TOC handler.
+
+	  If you don't want to debug the Kernel, so N.
+
 config PARISC_CPU_TOPOLOGY
 	bool "Support cpu topology definition"
 	depends on SMP
diff --git a/arch/parisc/include/asm/processor.h b/arch/parisc/include/asm/processor.h
index eeb7da064289..1e9a4c986921 100644
--- a/arch/parisc/include/asm/processor.h
+++ b/arch/parisc/include/asm/processor.h
@@ -294,6 +294,10 @@ extern int _parisc_requires_coherency;
 
 extern int running_on_qemu;
 
+extern void toc_handler(void);
+extern unsigned int toc_handler_size;
+extern unsigned int toc_handler_csum;
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* __ASM_PARISC_PROCESSOR_H */
diff --git a/arch/parisc/include/uapi/asm/pdc.h b/arch/parisc/include/uapi/asm/pdc.h
index ad51df8ba952..acc633c15722 100644
--- a/arch/parisc/include/uapi/asm/pdc.h
+++ b/arch/parisc/include/uapi/asm/pdc.h
@@ -398,8 +398,10 @@ struct zeropage {
 	/* int	(*vec_rendz)(void); */
 	unsigned int vec_rendz;
 	int	vec_pow_fail_flen;
-	int	vec_pad[10];		
-	
+	int	vec_pad0[3];
+	unsigned int vec_toc_hi;
+	int	vec_pad1[6];
+
 	/* [0x040] reserved processor dependent */
 	int	pad0[112];
 
diff --git a/arch/parisc/kernel/Makefile b/arch/parisc/kernel/Makefile
index 068d90950d93..ed0b87908d71 100644
--- a/arch/parisc/kernel/Makefile
+++ b/arch/parisc/kernel/Makefile
@@ -39,3 +39,4 @@ obj-$(CONFIG_KGDB)			+= kgdb.o
 obj-$(CONFIG_KPROBES)			+= kprobes.o
 obj-$(CONFIG_KEXEC_CORE)		+= kexec.o relocate_kernel.o
 obj-$(CONFIG_KEXEC_FILE)		+= kexec_file.o
+obj-$(CONFIG_TOC)			+= toc.o toc_asm.o
diff --git a/arch/parisc/kernel/toc.c b/arch/parisc/kernel/toc.c
new file mode 100644
index 000000000000..18327611cf8f
--- /dev/null
+++ b/arch/parisc/kernel/toc.c
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/kernel.h>
+#include <linux/kgdb.h>
+#include <linux/printk.h>
+#include <linux/sched/debug.h>
+#include <linux/delay.h>
+#include <linux/reboot.h>
+
+#include <asm/pdc.h>
+#include <asm/pdc_chassis.h>
+
+unsigned int __aligned(16) toc_lock = 1;
+
+static void toc20_to_pt_regs(struct pt_regs *regs, struct pdc_toc_pim_20 *toc)
+{
+	int i;
+
+	regs->gr[0] = (unsigned long)toc->cr[22];
+
+	for (i = 1; i < 32; i++)
+		regs->gr[i] = (unsigned long)toc->gr[i];
+
+	for (i = 0; i < 8; i++)
+		regs->sr[i] = (unsigned long)toc->sr[i];
+
+	regs->iasq[0] = (unsigned long)toc->cr[17];
+	regs->iasq[1] = (unsigned long)toc->iasq_back;
+	regs->iaoq[0] = (unsigned long)toc->cr[18];
+	regs->iaoq[1] = (unsigned long)toc->iaoq_back;
+
+	regs->sar = (unsigned long)toc->cr[11];
+	regs->iir = (unsigned long)toc->cr[19];
+	regs->isr = (unsigned long)toc->cr[20];
+	regs->ior = (unsigned long)toc->cr[21];
+}
+
+static void toc11_to_pt_regs(struct pt_regs *regs, struct pdc_toc_pim_11 *toc)
+{
+	int i;
+
+	regs->gr[0] = toc->cr[22];
+
+	for (i = 1; i < 32; i++)
+		regs->gr[i] = toc->gr[i];
+
+	for (i = 0; i < 8; i++)
+		regs->sr[i] = toc->sr[i];
+
+	regs->iasq[0] = toc->cr[17];
+	regs->iasq[1] = toc->iasq_back;
+	regs->iaoq[0] = toc->cr[18];
+	regs->iaoq[1] = toc->iaoq_back;
+
+	regs->sar  = toc->cr[11];
+	regs->iir  = toc->cr[19];
+	regs->isr  = toc->cr[20];
+	regs->ior  = toc->cr[21];
+}
+
+void notrace __noreturn __cold toc_intr(struct pt_regs *regs)
+{
+	struct pdc_toc_pim_20 pim_data20;
+	struct pdc_toc_pim_11 pim_data11;
+
+	nmi_enter();
+
+	if (boot_cpu_data.cpu_type >= pcxu) {
+		if (pdc_pim_toc20(&pim_data20))
+			panic("Failed to get PIM data");
+		toc20_to_pt_regs(regs, &pim_data20);
+	} else {
+		if (pdc_pim_toc11(&pim_data11))
+			panic("Failed to get PIM data");
+		toc11_to_pt_regs(regs, &pim_data11);
+	}
+
+#ifdef CONFIG_KGDB
+	if (atomic_read(&kgdb_active) != -1)
+		kgdb_nmicallback(raw_smp_processor_id(), regs);
+	kgdb_handle_exception(9, SIGTRAP, 0, regs);
+#endif
+	show_regs(regs);
+
+	/* give other CPUs time to show their backtrace */
+	mdelay(2000);
+	machine_restart("TOC");
+
+	/* should never reach this */
+	panic("TOC");
+}
+
+static __init int setup_toc(void)
+{
+	unsigned int csum = 0;
+	unsigned long toc_code = (unsigned long)dereference_function_descriptor(toc_handler);
+	int i;
+
+	PAGE0->vec_toc = __pa(toc_code) & 0xffffffff;
+#ifdef CONFIG_64BIT
+	PAGE0->vec_toc_hi = __pa(toc_code) >> 32;
+#endif
+	PAGE0->vec_toclen = toc_handler_size;
+
+	for (i = 0; i < toc_handler_size/4; i++)
+		csum += ((u32 *)toc_code)[i];
+	toc_handler_csum = -csum;
+	pr_info("TOC handler registered\n");
+	return 0;
+}
+early_initcall(setup_toc);
diff --git a/arch/parisc/kernel/toc_asm.S b/arch/parisc/kernel/toc_asm.S
new file mode 100644
index 000000000000..e94ba8044190
--- /dev/null
+++ b/arch/parisc/kernel/toc_asm.S
@@ -0,0 +1,88 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+/* TOC (Transfer of Control) handler. */
+
+	.level 1.1
+
+#include <asm/assembly.h>
+#include <asm/psw.h>
+#include <linux/threads.h>
+#include <linux/linkage.h>
+
+	.text
+	.import toc_intr,code
+	.import toc_lock,data
+	.align 16
+ENTRY_CFI(toc_handler)
+	/*
+	 * synchronize CPUs and obtain offset
+	 * for stack setup.
+	 */
+	load32		PA(toc_lock),%r1
+0:	ldcw,co		0(%r1),%r2
+	cmpib,=		0,%r2,0b
+	nop
+	addi		1,%r2,%r4
+	stw		%r4,0(%r1)
+	addi		-1,%r2,%r4
+
+	load32	PA(toc_stack),%sp
+	/*
+	 * deposit CPU number into stack address,
+	 * so every CPU will have its own stack.
+	 */
+	SHLREG	%r4,14,%r4
+	add	%r4,%sp,%sp
+
+	/*
+	 * setup pt_regs on stack and save the
+	 * floating point registers. PIM_TOC doesn't
+	 * save fp registers, so we're doing it here.
+	 */
+	copy	%sp,%arg0
+	ldo	PT_SZ_ALGN(%sp), %sp
+
+	/* clear pt_regs */
+	copy	%arg0,%r1
+0:	cmpb,<<,n %r1,%sp,0b
+	stw,ma	%r0,4(%r1)
+
+	ldo	PT_FR0(%arg0),%r25
+	save_fp	%r25
+
+	/* go virtual */
+	load32	PA(swapper_pg_dir),%r4
+	mtctl	%r4,%cr24
+	mtctl	%r4,%cr25
+
+	/* Clear sr4-sr7 */
+	mtsp	%r0, %sr4
+	mtsp	%r0, %sr5
+	mtsp	%r0, %sr6
+	mtsp	%r0, %sr7
+
+	tovirt_r1 %sp
+	tovirt_r1 %arg0
+	virt_map
+
+	loadgp
+
+#ifdef CONFIG_64BIT
+	ldo	-16(%sp),%r29
+#endif
+	load32	toc_intr,%r1
+	be	0(%sr7,%r1)
+	nop
+ENDPROC_CFI(toc_handler)
+
+	/*
+	 * keep this checksum here, as it is part of the toc_handler
+	 * spanned by toc_handler_size (all words in toc_handler are
+	 * added in PDC and the sum must equal to zero.
+	 */
+SYM_DATA(toc_handler_csum, .long 0)
+SYM_DATA(toc_handler_size, .long . - toc_handler)
+
+	__PAGE_ALIGNED_BSS
+	.align 64
+SYM_DATA(toc_stack, .block 16384*NR_CPUS)
-- 
2.33.0

Re: [PATCH v3 0/4] add TOC support

[Helge Deller]

On 10/14/21 21:49, Sven Schnelle wrote:
> This adds support for the TOC switches found on most PA-RISC
> machines. I tested this on my c8000 and a HP 16702A, which is
> basically a B160L with some logic analyzer hardware.
>
> Changes in v3:
> - add config option
> - move toc code to its own c & .S file
> - use early_initcall for setup
> - split out struct declarations
> - use sizeof(*ret) instead of sizeof(struct x)
> - move virt_map to assembly.h so it can be used from other files
>
> Changes in v2:
> - fix stack allocation
> - align toc_lock on 16 byte boundary
> - move toc_lock declaration to processor.c
>
> Sven Schnelle (4):
>   parisc: move virt_map macro to assembly.h
>   parisc: add PIM TOC data structures
>   parisc/firmware: add functions to retrieve TOC data
>   parisc: add support for TOC (transfer of control)
>
>  arch/parisc/Kconfig                 |  14 ++++
>  arch/parisc/include/asm/assembly.h  |  25 +++++++
>  arch/parisc/include/asm/pdc.h       |   2 +
>  arch/parisc/include/asm/processor.h |   4 +
>  arch/parisc/include/uapi/asm/pdc.h  |  28 ++++++-
>  arch/parisc/kernel/Makefile         |   1 +
>  arch/parisc/kernel/entry.S          |  24 ------
>  arch/parisc/kernel/firmware.c       |  32 ++++++++
>  arch/parisc/kernel/toc.c            | 111 ++++++++++++++++++++++++++++
>  arch/parisc/kernel/toc_asm.S        |  88 ++++++++++++++++++++++
>  10 files changed, 303 insertions(+), 26 deletions(-)
>  create mode 100644 arch/parisc/kernel/toc.c
>  create mode 100644 arch/parisc/kernel/toc_asm.S

I've just merged into the for-next-v5.15 git tree.

Thanks!
Helge

Re: [PATCH v3 4/4] parisc: add support for TOC (transfer of control)

[Rolf Eike Beer]

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Sven Schnelle wrote:

> diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
> index 27a8b49af11f..97a889eaffe1 100644
> --- a/arch/parisc/Kconfig
> +++ b/arch/parisc/Kconfig
> @@ -288,6 +288,20 @@ config SMP
> 
>  	  If you don't know what to do here, say N.
> 
> +config TOC
> +	bool "Support TOC switch"
> +	default y if 64BIT || !SMP
> +	help
> +	  Most PA-RISC machines have either a switch at the back of the 
machine
> +	  or a command in BMC to trigger a TOC interrupt. If you say Y here 
a
> +	  handler will be installed which will either show a backtrace on 
all
> +	  CPUs, or enter a possible configured debugger like kgdb/kdb.
> +
> +	  Note that with this option enabled, the kernel will use an 
additional
> 16KB +	  per possible CPU as a special stack for the TOC handler.
> +
> +	  If you don't want to debug the Kernel, so N.

so -> say?

> +void notrace __noreturn __cold toc_intr(struct pt_regs *regs)
> +{
> +	struct pdc_toc_pim_20 pim_data20;
> +	struct pdc_toc_pim_11 pim_data11;
> +
> +	nmi_enter();
> +
> +	if (boot_cpu_data.cpu_type >= pcxu) {
> +		if (pdc_pim_toc20(&pim_data20))
> +			panic("Failed to get PIM data");
> +		toc20_to_pt_regs(regs, &pim_data20);
> +	} else {
> +		if (pdc_pim_toc11(&pim_data11))
> +			panic("Failed to get PIM data");
> +		toc11_to_pt_regs(regs, &pim_data11);
> +	}

As I said elsewhere because I had missed v3: move the variables in the if 
branches.

Eike

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Re: [PATCH v3 4/4] parisc: add support for TOC (transfer of control)

[Helge Deller]

On 10/16/21 18:49, Rolf Eike Beer wrote:
> Sven Schnelle wrote:
>
>> diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
>> index 27a8b49af11f..97a889eaffe1 100644
>> --- a/arch/parisc/Kconfig
>> +++ b/arch/parisc/Kconfig
>> @@ -288,6 +288,20 @@ config SMP
>>
>>  	  If you don't know what to do here, say N.
>>
>> +config TOC
>> +	bool "Support TOC switch"
>> +	default y if 64BIT || !SMP
>> +	help
>> +	  Most PA-RISC machines have either a switch at the back of the
> machine
>> +	  or a command in BMC to trigger a TOC interrupt. If you say Y here
> a
>> +	  handler will be installed which will either show a backtrace on
> all
>> +	  CPUs, or enter a possible configured debugger like kgdb/kdb.
>> +
>> +	  Note that with this option enabled, the kernel will use an
> additional
>> 16KB +	  per possible CPU as a special stack for the TOC handler.
>> +
>> +	  If you don't want to debug the Kernel, so N.
>
> so -> say?

Yes, I fixed that before I applied to my tree.

>> +void notrace __noreturn __cold toc_intr(struct pt_regs *regs)
>> +{
>> +	struct pdc_toc_pim_20 pim_data20;
>> +	struct pdc_toc_pim_11 pim_data11;
>> +
>> +	nmi_enter();
>> +
>> +	if (boot_cpu_data.cpu_type >= pcxu) {
>> +		if (pdc_pim_toc20(&pim_data20))
>> +			panic("Failed to get PIM data");
>> +		toc20_to_pt_regs(regs, &pim_data20);
>> +	} else {
>> +		if (pdc_pim_toc11(&pim_data11))
>> +			panic("Failed to get PIM data");
>> +		toc11_to_pt_regs(regs, &pim_data11);
>> +	}
>
> As I said elsewhere because I had missed v3: move the variables in the if
> branches.

It won't change anything, the compiler is clever enough to optimize it.
Another option would be to completely move the pdc_pim_toc* functions
into the toc*_to_pt_regs functions, maybe then renaming them to
get_tocXX_pt_regs(regs);

Helge