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* Re: [PATCH v3 03/41] KVM: PPC: Book3S HV: Remove redundant mtspr PSPB
From: Daniel Axtens @ 2021-03-12  5:07 UTC (permalink / raw)
  To: Nicholas Piggin, kvm-ppc; +Cc: linuxppc-dev, Nicholas Piggin, Fabiano Rosas
In-Reply-To: <20210305150638.2675513-4-npiggin@gmail.com>

Hi Nick,

> This SPR is set to 0 twice when exiting the guest.
>
Indeed it is.

I checked the ISA because I'd never heard of the PSPB SPR before! It's
the Problem State Priority Boost register. Before I knew what it was, I
was slightly concerned that the chip might change the value while the
other mtsprs were running, but given that it's just affects the priority
boost states that problem state can use, I don't think that is actually
going to happen.

I also checked the commit that introduced it - commit 95a6432ce903
("KVM: PPC: Book3S HV: Streamlined guest entry/exit path on P9 for radix
guests"), and there wasn't any justification for having a double mtspr.

So, this seems good:
Reviewed-by: Daniel Axtens <dja@axtens.net>

Kind regards,
Daniel


> Suggested-by: Fabiano Rosas <farosas@linux.ibm.com>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
>  arch/powerpc/kvm/book3s_hv.c | 1 -
>  1 file changed, 1 deletion(-)
>
> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> index 2e29b96ef775..0542d7f17dc3 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -3758,7 +3758,6 @@ static int kvmhv_p9_guest_entry(struct kvm_vcpu *vcpu, u64 time_limit,
>  	mtspr(SPRN_DSCR, host_dscr);
>  	mtspr(SPRN_TIDR, host_tidr);
>  	mtspr(SPRN_IAMR, host_iamr);
> -	mtspr(SPRN_PSPB, 0);
>
>  	if (host_amr != vcpu->arch.amr)
>  		mtspr(SPRN_AMR, host_amr);
> -- 
> 2.23.0

^ permalink raw reply

* Re: [PATCH v3 12/41] KVM: PPC: Book3S 64: Move hcall early register setup to KVM
From: Daniel Axtens @ 2021-03-12  5:45 UTC (permalink / raw)
  To: Nicholas Piggin, kvm-ppc; +Cc: linuxppc-dev, Nicholas Piggin
In-Reply-To: <20210305150638.2675513-13-npiggin@gmail.com>

Nicholas Piggin <npiggin@gmail.com> writes:

> System calls / hcalls have a different calling convention than
> other interrupts, so there is code in the KVMTEST to massage these
> into the same form as other interrupt handlers.
>
> Move this work into the KVM hcall handler. This means teaching KVM
> a little more about the low level interrupt handler setup, PACA save
> areas, etc., although that's not obviously worse than the current
> approach of coming up with an entirely different interrupt register
> / save convention.
>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
>  arch/powerpc/include/asm/exception-64s.h | 13 ++++++++
>  arch/powerpc/kernel/exceptions-64s.S     | 42 +-----------------------
>  arch/powerpc/kvm/book3s_64_entry.S       | 17 ++++++++++
>  3 files changed, 31 insertions(+), 41 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h
> index c1a8aac01cf9..bb6f78fcf981 100644
> --- a/arch/powerpc/include/asm/exception-64s.h
> +++ b/arch/powerpc/include/asm/exception-64s.h
> @@ -35,6 +35,19 @@
>  /* PACA save area size in u64 units (exgen, exmc, etc) */
>  #define EX_SIZE		10
>  
> +/* PACA save area offsets */
> +#define EX_R9		0
> +#define EX_R10		8
> +#define EX_R11		16
> +#define EX_R12		24
> +#define EX_R13		32
> +#define EX_DAR		40
> +#define EX_DSISR	48
> +#define EX_CCR		52
> +#define EX_CFAR		56
> +#define EX_PPR		64
> +#define EX_CTR		72
> +
>  /*
>   * maximum recursive depth of MCE exceptions
>   */
> diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
> index 292435bd80f0..b7092ba87da8 100644
> --- a/arch/powerpc/kernel/exceptions-64s.S
> +++ b/arch/powerpc/kernel/exceptions-64s.S
> @@ -21,22 +21,6 @@
>  #include <asm/feature-fixups.h>
>  #include <asm/kup.h>
>  
> -/* PACA save area offsets (exgen, exmc, etc) */
> -#define EX_R9		0
> -#define EX_R10		8
> -#define EX_R11		16
> -#define EX_R12		24
> -#define EX_R13		32
> -#define EX_DAR		40
> -#define EX_DSISR	48
> -#define EX_CCR		52
> -#define EX_CFAR		56
> -#define EX_PPR		64
> -#define EX_CTR		72
> -.if EX_SIZE != 10
> -	.error "EX_SIZE is wrong"
> -.endif
> -
>  /*
>   * Following are fixed section helper macros.
>   *
> @@ -1964,29 +1948,8 @@ EXC_VIRT_END(system_call, 0x4c00, 0x100)
>  
>  #ifdef CONFIG_KVM_BOOK3S_64_HANDLER
>  TRAMP_REAL_BEGIN(system_call_kvm)
> -	/*
> -	 * This is a hcall, so register convention is as above, with these
> -	 * differences:
> -	 * r13 = PACA
> -	 * ctr = orig r13
> -	 * orig r10 saved in PACA
> -	 */
> -	 /*
> -	  * Save the PPR (on systems that support it) before changing to
> -	  * HMT_MEDIUM. That allows the KVM code to save that value into the
> -	  * guest state (it is the guest's PPR value).
> -	  */
> -BEGIN_FTR_SECTION
> -	mfspr	r10,SPRN_PPR
> -	std	r10,HSTATE_PPR(r13)
> -END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
> -	HMT_MEDIUM
>  	mfctr	r10
> -	SET_SCRATCH0(r10)
> -	mfcr	r10
> -	std	r12,HSTATE_SCRATCH0(r13)
> -	sldi	r12,r10,32
> -	ori	r12,r12,0xc00
> +	SET_SCRATCH0(r10) /* Save r13 in SCRATCH0 */

If I've understood correctly, you've saved the _original_/guest r13 in
SCRATCH0. That makes sense - it just took me a while to follow the
logic, especially because the parameter to SET_SCRATCH0 is r10, not r13.

I would probably expand the comment to say the original or guest r13 (as
you do in the comment at the start of kvmppc_hcall), but if there's a
convention here that I've missed that might not be necessary.

>  #ifdef CONFIG_RELOCATABLE
>  	/*
>  	 * Requires __LOAD_FAR_HANDLER beause kvmppc_hcall lives
> @@ -1994,15 +1957,12 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
>  	 */
>  	__LOAD_FAR_HANDLER(r10, kvmppc_hcall)
>  	mtctr   r10
> -	ld	r10,PACA_EXGEN+EX_R10(r13)
>  	bctr
>  #else
> -	ld	r10,PACA_EXGEN+EX_R10(r13)
>  	b       kvmppc_hcall
>  #endif
>  #endif
>  
> -
>  /**
>   * Interrupt 0xd00 - Trace Interrupt.
>   * This is a synchronous interrupt in response to instruction step or
> diff --git a/arch/powerpc/kvm/book3s_64_entry.S b/arch/powerpc/kvm/book3s_64_entry.S
> index 8cf5e24a81eb..a7b6edd18bc8 100644
> --- a/arch/powerpc/kvm/book3s_64_entry.S
> +++ b/arch/powerpc/kvm/book3s_64_entry.S
> @@ -14,6 +14,23 @@
>  .global	kvmppc_hcall
>  .balign IFETCH_ALIGN_BYTES
>  kvmppc_hcall:
> +	/*
> +	 * This is a hcall, so register convention is as
> +	 * Documentation/powerpc/papr_hcalls.rst, with these additions:
> +	 * R13		= PACA
> +	 * guest R13 saved in SPRN_SCRATCH0
> +	 * R10		= free
> +	 */
> +BEGIN_FTR_SECTION
> +	mfspr	r10,SPRN_PPR
> +	std	r10,HSTATE_PPR(r13)
> +END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)

Do we want to preserve the comment about why we save the PPR?

> +	HMT_MEDIUM
> +	mfcr	r10
> +	std	r12,HSTATE_SCRATCH0(r13)
> +	sldi	r12,r10,32
> +	ori	r12,r12,0xc00

I see that this is a direct copy from the earlier code, but it confuses
me a bit. Looking at exceptions-64s.S, there's the following comment:

 * In HPT, sc 1 always goes to 0xc00 real mode. In RADIX, sc 1 can go to
 * 0x4c00 virtual mode.

However, this code uncondionally sets the low bits to be c00, even if
the exception came in via 4c00. Is this right? Do we need to pass
that through somehow?

> +	ld	r10,PACA_EXGEN+EX_R10(r13)
>

Otherwise, this looks good to me so far.

Kind regards,
Daniel

>  .global	kvmppc_interrupt
>  .balign IFETCH_ALIGN_BYTES
> -- 
> 2.23.0

^ permalink raw reply

* [PATCH 0/3] powerpc/mm/hash: Time improvements for memory hot(un)plug
From: Leonardo Bras @ 2021-03-12  7:29 UTC (permalink / raw)
  To: Michael Ellerman, Benjamin Herrenschmidt, Paul Mackerras,
	Andrew Morton, Leonardo Bras, Sandipan Das, Aneesh Kumar K.V,
	Logan Gunthorpe, Mike Rapoport, Bharata B Rao, Dan Williams,
	Nicholas Piggin, Nathan Lynch, David Hildenbrand, Laurent Dufour,
	Scott Cheloha, David Gibson
  Cc: linuxppc-dev, linux-kernel

This patchset intends to reduce time needed for processing memory
hotplug/hotunplug in hash guests.

The first one, makes sure guests with pagesize over 4k don't need to
go through HPT resize-downs after memory hotplug.

The second and third patches make hotplug / hotunplug perform a single
HPT resize per operation, instead of one for each shift change, or one
for each LMB in case of resize-down error.

Why haven't the same mechanism used for both memory hotplug and hotunplug?
They both have different requirements:

Memory hotplug causes (usually) HPT resize-ups, which are fine happening
at the start of hotplug, but resize-ups should not ever be disabled, as
other mechanisms may try to increase memory, hitting issues with a HPT
that is too small.

Memory hotunplug causes HPT resize-downs, which can be disabled (HPT will
just remain larger for a while), but need to happen at the end of an
hotunplug operation. If we want to batch it, we need to disable
resize-downs and perform it only at the end.

Tests done with this patchset in the same machine / guest config:
Starting memory: 129GB, DIMM: 256GB
Before patchset: hotplug = 710s, hotunplug = 621s.
After patchset: hotplug  = 21s, hotunplug = 100s.

Any feedback will be appreciated!
I believe the code may not be very well placed in available files,
so please give some feedback on that.

Best regards,

Leonardo Bras (3):
  powerpc/mm/hash: Avoid resizing-down HPT on first memory hotplug
  powerpc/mm/hash: Avoid multiple HPT resize-ups on memory hotplug
  powerpc/mm/hash: Avoid multiple HPT resize-downs on memory hotunplug

 arch/powerpc/include/asm/book3s/64/hash.h     |  4 +
 arch/powerpc/include/asm/sparsemem.h          |  4 +
 arch/powerpc/mm/book3s64/hash_utils.c         | 78 +++++++++++++++----
 arch/powerpc/mm/book3s64/pgtable.c            | 18 +++++
 .../platforms/pseries/hotplug-memory.c        | 22 ++++++
 5 files changed, 111 insertions(+), 15 deletions(-)

-- 
2.29.2


^ permalink raw reply

* [PATCH 1/3] powerpc/mm/hash: Avoid resizing-down HPT on first memory hotplug
From: Leonardo Bras @ 2021-03-12  7:29 UTC (permalink / raw)
  To: Michael Ellerman, Benjamin Herrenschmidt, Paul Mackerras,
	Andrew Morton, Leonardo Bras, Sandipan Das, Aneesh Kumar K.V,
	Logan Gunthorpe, Mike Rapoport, Bharata B Rao, Dan Williams,
	Nicholas Piggin, Nathan Lynch, David Hildenbrand, Laurent Dufour,
	Scott Cheloha, David Gibson
  Cc: linuxppc-dev, linux-kernel
In-Reply-To: <20210312072940.598696-1-leobras.c@gmail.com>

Because hypervisors may need to create HPTs without knowing the guest
page size, the smallest used page-size (4k) may be chosen, resulting in
a HPT that is possibly bigger than needed.

On a guest with bigger page-sizes, the amount of entries for HTP may be
too high, causing the guest to ask for a HPT resize-down on the first
hotplug.

This becomes a problem when HPT resize-down fails, and causes the
HPT resize to be performed on every LMB added, until HPT size is
compatible to guest memory size, causing a major slowdown.

So, avoiding HPT resizing-down on hot-add significantly improves memory
hotplug times.

As an example, hotplugging 256GB on a 129GB guest took 710s without this
patch, and 21s after applied.

Signed-off-by: Leonardo Bras <leobras.c@gmail.com>
---
 arch/powerpc/mm/book3s64/hash_utils.c | 36 ++++++++++++++++-----------
 1 file changed, 21 insertions(+), 15 deletions(-)

diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c
index 73b06adb6eeb..cfb3ec164f56 100644
--- a/arch/powerpc/mm/book3s64/hash_utils.c
+++ b/arch/powerpc/mm/book3s64/hash_utils.c
@@ -794,7 +794,7 @@ static unsigned long __init htab_get_table_size(void)
 }
 
 #ifdef CONFIG_MEMORY_HOTPLUG
-static int resize_hpt_for_hotplug(unsigned long new_mem_size)
+static int resize_hpt_for_hotplug(unsigned long new_mem_size, bool shrinking)
 {
 	unsigned target_hpt_shift;
 
@@ -803,19 +803,25 @@ static int resize_hpt_for_hotplug(unsigned long new_mem_size)
 
 	target_hpt_shift = htab_shift_for_mem_size(new_mem_size);
 
-	/*
-	 * To avoid lots of HPT resizes if memory size is fluctuating
-	 * across a boundary, we deliberately have some hysterisis
-	 * here: we immediately increase the HPT size if the target
-	 * shift exceeds the current shift, but we won't attempt to
-	 * reduce unless the target shift is at least 2 below the
-	 * current shift
-	 */
-	if (target_hpt_shift > ppc64_pft_size ||
-	    target_hpt_shift < ppc64_pft_size - 1)
-		return mmu_hash_ops.resize_hpt(target_hpt_shift);
+	if (shrinking) {
 
-	return 0;
+		/*
+		 * To avoid lots of HPT resizes if memory size is fluctuating
+		 * across a boundary, we deliberately have some hysterisis
+		 * here: we immediately increase the HPT size if the target
+		 * shift exceeds the current shift, but we won't attempt to
+		 * reduce unless the target shift is at least 2 below the
+		 * current shift
+		 */
+
+		if (target_hpt_shift >= ppc64_pft_size - 1)
+			return 0;
+
+	} else if (target_hpt_shift <= ppc64_pft_size) {
+		return 0;
+	}
+
+	return mmu_hash_ops.resize_hpt(target_hpt_shift);
 }
 
 int hash__create_section_mapping(unsigned long start, unsigned long end,
@@ -828,7 +834,7 @@ int hash__create_section_mapping(unsigned long start, unsigned long end,
 		return -1;
 	}
 
-	resize_hpt_for_hotplug(memblock_phys_mem_size());
+	resize_hpt_for_hotplug(memblock_phys_mem_size(), false);
 
 	rc = htab_bolt_mapping(start, end, __pa(start),
 			       pgprot_val(prot), mmu_linear_psize,
@@ -847,7 +853,7 @@ int hash__remove_section_mapping(unsigned long start, unsigned long end)
 	int rc = htab_remove_mapping(start, end, mmu_linear_psize,
 				     mmu_kernel_ssize);
 
-	if (resize_hpt_for_hotplug(memblock_phys_mem_size()) == -ENOSPC)
+	if (resize_hpt_for_hotplug(memblock_phys_mem_size(), true) == -ENOSPC)
 		pr_warn("Hash collision while resizing HPT\n");
 
 	return rc;
-- 
2.29.2


^ permalink raw reply related

* [PATCH 2/3] powerpc/mm/hash: Avoid multiple HPT resize-ups on memory hotplug
From: Leonardo Bras @ 2021-03-12  7:29 UTC (permalink / raw)
  To: Michael Ellerman, Benjamin Herrenschmidt, Paul Mackerras,
	Andrew Morton, Leonardo Bras, Sandipan Das, Aneesh Kumar K.V,
	Logan Gunthorpe, Mike Rapoport, Bharata B Rao, Dan Williams,
	Nicholas Piggin, Nathan Lynch, David Hildenbrand, Laurent Dufour,
	Scott Cheloha, David Gibson
  Cc: linuxppc-dev, linux-kernel
In-Reply-To: <20210312072940.598696-1-leobras.c@gmail.com>

Every time a memory hotplug happens, and the memory limit crosses a 2^n
value, it may be necessary to perform HPT resizing-up, which can take
some time (over 100ms in my tests).

It usually is not an issue, but it can take some time if a lot of memory
is added to a guest with little starting memory:
Adding 256G to a 2GB guest, for example will require 8 HPT resizes.

Perform an HPT resize before memory hotplug, updating HPT to its
final size (considering a successful hotplug), taking the number of
HPT resizes to at most one per memory hotplug action.

Signed-off-by: Leonardo Bras <leobras.c@gmail.com>
---
 arch/powerpc/include/asm/book3s/64/hash.h       |  2 ++
 arch/powerpc/include/asm/sparsemem.h            |  2 ++
 arch/powerpc/mm/book3s64/hash_utils.c           | 14 ++++++++++++++
 arch/powerpc/mm/book3s64/pgtable.c              |  6 ++++++
 arch/powerpc/platforms/pseries/hotplug-memory.c |  6 ++++++
 5 files changed, 30 insertions(+)

diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h
index d959b0195ad9..843b0a178590 100644
--- a/arch/powerpc/include/asm/book3s/64/hash.h
+++ b/arch/powerpc/include/asm/book3s/64/hash.h
@@ -255,6 +255,8 @@ int hash__create_section_mapping(unsigned long start, unsigned long end,
 				 int nid, pgprot_t prot);
 int hash__remove_section_mapping(unsigned long start, unsigned long end);
 
+void hash_memory_batch_expand_prepare(unsigned long newsize);
+
 #endif /* !__ASSEMBLY__ */
 #endif /* __KERNEL__ */
 #endif /* _ASM_POWERPC_BOOK3S_64_HASH_H */
diff --git a/arch/powerpc/include/asm/sparsemem.h b/arch/powerpc/include/asm/sparsemem.h
index d072866842e4..16b5f5300c84 100644
--- a/arch/powerpc/include/asm/sparsemem.h
+++ b/arch/powerpc/include/asm/sparsemem.h
@@ -17,6 +17,8 @@ extern int remove_section_mapping(unsigned long start, unsigned long end);
 extern int memory_add_physaddr_to_nid(u64 start);
 #define memory_add_physaddr_to_nid memory_add_physaddr_to_nid
 
+void memory_batch_expand_prepare(unsigned long newsize);
+
 #ifdef CONFIG_NUMA
 extern int hot_add_scn_to_nid(unsigned long scn_addr);
 #else
diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c
index cfb3ec164f56..1f6aa0bf27e7 100644
--- a/arch/powerpc/mm/book3s64/hash_utils.c
+++ b/arch/powerpc/mm/book3s64/hash_utils.c
@@ -858,6 +858,20 @@ int hash__remove_section_mapping(unsigned long start, unsigned long end)
 
 	return rc;
 }
+
+void hash_memory_batch_expand_prepare(unsigned long newsize)
+{
+	/*
+	 * Resizing-up HPT should never fail, but there are some cases system starts with higher
+	 * SHIFT than required, and we go through the funny case of resizing HPT down while
+	 * adding memory
+	 */
+
+	while (resize_hpt_for_hotplug(newsize, false) == -ENOSPC) {
+		newsize *= 2;
+		pr_warn("Hash collision while resizing HPT\n");
+	}
+}
 #endif /* CONFIG_MEMORY_HOTPLUG */
 
 static void __init hash_init_partition_table(phys_addr_t hash_table,
diff --git a/arch/powerpc/mm/book3s64/pgtable.c b/arch/powerpc/mm/book3s64/pgtable.c
index 5b3a3bae21aa..f1cd8af0f67f 100644
--- a/arch/powerpc/mm/book3s64/pgtable.c
+++ b/arch/powerpc/mm/book3s64/pgtable.c
@@ -193,6 +193,12 @@ int __meminit remove_section_mapping(unsigned long start, unsigned long end)
 
 	return hash__remove_section_mapping(start, end);
 }
+
+void memory_batch_expand_prepare(unsigned long newsize)
+{
+	if (!radix_enabled())
+		hash_memory_batch_expand_prepare(newsize);
+}
 #endif /* CONFIG_MEMORY_HOTPLUG */
 
 void __init mmu_partition_table_init(void)
diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
index 8377f1f7c78e..353c71249214 100644
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -671,6 +671,8 @@ static int dlpar_memory_add_by_count(u32 lmbs_to_add)
 	if (lmbs_available < lmbs_to_add)
 		return -EINVAL;
 
+	memory_batch_expand_prepare(memblock_phys_mem_size() + lmbs_to_add * drmem_lmb_size());
+
 	for_each_drmem_lmb(lmb) {
 		if (lmb->flags & DRCONF_MEM_ASSIGNED)
 			continue;
@@ -734,6 +736,8 @@ static int dlpar_memory_add_by_index(u32 drc_index)
 
 	pr_info("Attempting to hot-add LMB, drc index %x\n", drc_index);
 
+	memory_batch_expand_prepare(memblock_phys_mem_size() +
+				     drmem_info->n_lmbs * drmem_lmb_size());
 	lmb_found = 0;
 	for_each_drmem_lmb(lmb) {
 		if (lmb->drc_index == drc_index) {
@@ -788,6 +792,8 @@ static int dlpar_memory_add_by_ic(u32 lmbs_to_add, u32 drc_index)
 	if (lmbs_available < lmbs_to_add)
 		return -EINVAL;
 
+	memory_batch_expand_prepare(memblock_phys_mem_size() + lmbs_to_add * drmem_lmb_size());
+
 	for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {
 		if (lmb->flags & DRCONF_MEM_ASSIGNED)
 			continue;
-- 
2.29.2


^ permalink raw reply related

* [PATCH 3/3] powerpc/mm/hash: Avoid multiple HPT resize-downs on memory hotunplug
From: Leonardo Bras @ 2021-03-12  7:29 UTC (permalink / raw)
  To: Michael Ellerman, Benjamin Herrenschmidt, Paul Mackerras,
	Andrew Morton, Leonardo Bras, Sandipan Das, Aneesh Kumar K.V,
	Logan Gunthorpe, Mike Rapoport, Bharata B Rao, Dan Williams,
	Nicholas Piggin, Nathan Lynch, David Hildenbrand, Laurent Dufour,
	Scott Cheloha, David Gibson
  Cc: linuxppc-dev, linux-kernel
In-Reply-To: <20210312072940.598696-1-leobras.c@gmail.com>

During memory hotunplug, after each LMB is removed, the HPT may be
resized-down if it would map a max of 4 times the current amount of memory.
(2 shifts, due to introduced histeresis)

It usually is not an issue, but it can take a lot of time if HPT
resizing-down fails. This happens  because resize-down failures
usually repeat at each LMB removal, until there are no more bolted entries
conflict, which can take a while to happen.

This can be solved by doing a single HPT resize at the end of memory
hotunplug, after all requested entries are removed.

To make this happen, it's necessary to temporarily disable all HPT
resize-downs before hotunplug, re-enable them after hotunplug ends,
and then resize-down HPT to the current memory size.

As an example, hotunplugging 256GB from a 385GB guest took 621s without
this patch, and 100s after applied.

Signed-off-by: Leonardo Bras <leobras.c@gmail.com>
---
 arch/powerpc/include/asm/book3s/64/hash.h     |  2 ++
 arch/powerpc/include/asm/sparsemem.h          |  2 ++
 arch/powerpc/mm/book3s64/hash_utils.c         | 28 +++++++++++++++++++
 arch/powerpc/mm/book3s64/pgtable.c            | 12 ++++++++
 .../platforms/pseries/hotplug-memory.c        | 16 +++++++++++
 5 files changed, 60 insertions(+)

diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h
index 843b0a178590..f92697c107f7 100644
--- a/arch/powerpc/include/asm/book3s/64/hash.h
+++ b/arch/powerpc/include/asm/book3s/64/hash.h
@@ -256,6 +256,8 @@ int hash__create_section_mapping(unsigned long start, unsigned long end,
 int hash__remove_section_mapping(unsigned long start, unsigned long end);
 
 void hash_memory_batch_expand_prepare(unsigned long newsize);
+void hash_memory_batch_shrink_begin(void);
+void hash_memory_batch_shrink_end(void);
 
 #endif /* !__ASSEMBLY__ */
 #endif /* __KERNEL__ */
diff --git a/arch/powerpc/include/asm/sparsemem.h b/arch/powerpc/include/asm/sparsemem.h
index 16b5f5300c84..a7a8a0d070fc 100644
--- a/arch/powerpc/include/asm/sparsemem.h
+++ b/arch/powerpc/include/asm/sparsemem.h
@@ -18,6 +18,8 @@ extern int memory_add_physaddr_to_nid(u64 start);
 #define memory_add_physaddr_to_nid memory_add_physaddr_to_nid
 
 void memory_batch_expand_prepare(unsigned long newsize);
+void memory_batch_shrink_begin(void);
+void memory_batch_shrink_end(void);
 
 #ifdef CONFIG_NUMA
 extern int hot_add_scn_to_nid(unsigned long scn_addr);
diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c
index 1f6aa0bf27e7..e16f207de8e4 100644
--- a/arch/powerpc/mm/book3s64/hash_utils.c
+++ b/arch/powerpc/mm/book3s64/hash_utils.c
@@ -794,6 +794,9 @@ static unsigned long __init htab_get_table_size(void)
 }
 
 #ifdef CONFIG_MEMORY_HOTPLUG
+
+atomic_t hpt_resize_disable = ATOMIC_INIT(0);
+
 static int resize_hpt_for_hotplug(unsigned long new_mem_size, bool shrinking)
 {
 	unsigned target_hpt_shift;
@@ -805,6 +808,10 @@ static int resize_hpt_for_hotplug(unsigned long new_mem_size, bool shrinking)
 
 	if (shrinking) {
 
+		/* When batch removing entries, only resizes HPT at the end. */
+		if (atomic_read_acquire(&hpt_resize_disable))
+			return 0;
+
 		/*
 		 * To avoid lots of HPT resizes if memory size is fluctuating
 		 * across a boundary, we deliberately have some hysterisis
@@ -872,6 +879,27 @@ void hash_memory_batch_expand_prepare(unsigned long newsize)
 		pr_warn("Hash collision while resizing HPT\n");
 	}
 }
+
+void hash_memory_batch_shrink_begin(void)
+{
+	/* Disable HPT resize-down during hot-unplug */
+	atomic_set_release(&hpt_resize_disable, 1);
+}
+
+void hash_memory_batch_shrink_end(void)
+{
+	unsigned long newsize;
+
+	/* Re-enables HPT resize-down after hot-unplug */
+	atomic_set_release(&hpt_resize_disable, 0);
+
+	newsize = memblock_phys_mem_size();
+	/* Resize to smallest SHIFT possible */
+	while (resize_hpt_for_hotplug(newsize, true) == -ENOSPC) {
+		newsize *= 2;
+		pr_warn("Hash collision while resizing HPT\n");
+	}
+}
 #endif /* CONFIG_MEMORY_HOTPLUG */
 
 static void __init hash_init_partition_table(phys_addr_t hash_table,
diff --git a/arch/powerpc/mm/book3s64/pgtable.c b/arch/powerpc/mm/book3s64/pgtable.c
index f1cd8af0f67f..e01681e22e00 100644
--- a/arch/powerpc/mm/book3s64/pgtable.c
+++ b/arch/powerpc/mm/book3s64/pgtable.c
@@ -199,6 +199,18 @@ void memory_batch_expand_prepare(unsigned long newsize)
 	if (!radix_enabled())
 		hash_memory_batch_expand_prepare(newsize);
 }
+
+void memory_batch_shrink_begin(void)
+{
+	if (!radix_enabled())
+		hash_memory_batch_shrink_begin();
+}
+
+void memory_batch_shrink_end(void)
+{
+	if (!radix_enabled())
+		hash_memory_batch_shrink_end();
+}
 #endif /* CONFIG_MEMORY_HOTPLUG */
 
 void __init mmu_partition_table_init(void)
diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
index 353c71249214..9182fb5b5c01 100644
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -425,6 +425,8 @@ static int dlpar_memory_remove_by_count(u32 lmbs_to_remove)
 		return -EINVAL;
 	}
 
+	memory_batch_shrink_begin();
+
 	for_each_drmem_lmb(lmb) {
 		rc = dlpar_remove_lmb(lmb);
 		if (rc)
@@ -470,6 +472,8 @@ static int dlpar_memory_remove_by_count(u32 lmbs_to_remove)
 		rc = 0;
 	}
 
+	memory_batch_shrink_end();
+
 	return rc;
 }
 
@@ -481,6 +485,8 @@ static int dlpar_memory_remove_by_index(u32 drc_index)
 
 	pr_debug("Attempting to hot-remove LMB, drc index %x\n", drc_index);
 
+	memory_batch_shrink_begin();
+
 	lmb_found = 0;
 	for_each_drmem_lmb(lmb) {
 		if (lmb->drc_index == drc_index) {
@@ -502,6 +508,8 @@ static int dlpar_memory_remove_by_index(u32 drc_index)
 	else
 		pr_debug("Memory at %llx was hot-removed\n", lmb->base_addr);
 
+	memory_batch_shrink_end();
+
 	return rc;
 }
 
@@ -532,6 +540,8 @@ static int dlpar_memory_remove_by_ic(u32 lmbs_to_remove, u32 drc_index)
 	if (lmbs_available < lmbs_to_remove)
 		return -EINVAL;
 
+	memory_batch_shrink_begin();
+
 	for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {
 		if (!(lmb->flags & DRCONF_MEM_ASSIGNED))
 			continue;
@@ -572,6 +582,8 @@ static int dlpar_memory_remove_by_ic(u32 lmbs_to_remove, u32 drc_index)
 		}
 	}
 
+	memory_batch_shrink_end();
+
 	return rc;
 }
 
@@ -700,6 +712,7 @@ static int dlpar_memory_add_by_count(u32 lmbs_to_add)
 	if (lmbs_added != lmbs_to_add) {
 		pr_err("Memory hot-add failed, removing any added LMBs\n");
 
+		memory_batch_shrink_begin();
 		for_each_drmem_lmb(lmb) {
 			if (!drmem_lmb_reserved(lmb))
 				continue;
@@ -713,6 +726,7 @@ static int dlpar_memory_add_by_count(u32 lmbs_to_add)
 
 			drmem_remove_lmb_reservation(lmb);
 		}
+		memory_batch_shrink_end();
 		rc = -EINVAL;
 	} else {
 		for_each_drmem_lmb(lmb) {
@@ -814,6 +828,7 @@ static int dlpar_memory_add_by_ic(u32 lmbs_to_add, u32 drc_index)
 	if (rc) {
 		pr_err("Memory indexed-count-add failed, removing any added LMBs\n");
 
+		memory_batch_shrink_begin();
 		for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {
 			if (!drmem_lmb_reserved(lmb))
 				continue;
@@ -827,6 +842,7 @@ static int dlpar_memory_add_by_ic(u32 lmbs_to_add, u32 drc_index)
 
 			drmem_remove_lmb_reservation(lmb);
 		}
+		memory_batch_shrink_end();
 		rc = -EINVAL;
 	} else {
 		for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {
-- 
2.29.2


^ permalink raw reply related

* Re: [PATCH v2 25/43] powerpc/32: Replace ASM exception exit by C exception exit from ppc64
From: Christophe Leroy @ 2021-03-12  8:28 UTC (permalink / raw)
  To: Michael Ellerman, Benjamin Herrenschmidt, Paul Mackerras, npiggin
  Cc: linuxppc-dev, linux-kernel
In-Reply-To: <87r1kljmr9.fsf@mpe.ellerman.id.au>



Le 12/03/2021 à 00:26, Michael Ellerman a écrit :
> Christophe Leroy <christophe.leroy@csgroup.eu> writes:
>> Le 11/03/2021 à 14:46, Michael Ellerman a écrit :
>>> Christophe Leroy <christophe.leroy@csgroup.eu> writes:
>>>> This patch replaces the PPC32 ASM exception exit by C exception exit.
>>>>
>>>> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
>>>> ---
>>>>    arch/powerpc/kernel/entry_32.S  | 481 +++++++++-----------------------
>>>>    arch/powerpc/kernel/interrupt.c |   4 +
>>>>    2 files changed, 132 insertions(+), 353 deletions(-)
>>>
>>> Bisect points to this breaking qemu mac99 for me, with pmac32_defconfig.
>>>
>>> I haven't had time to dig any deeper sorry.
>>
>> Embarrasing ...
> 
> Nah, these things happen.
> 
>> I don't get this problem on the 8xx (nohash/32) or the 83xx (book3s/32).
>> I don't get this problem with qemu mac99 when using my klibc-based initramfs.
>>
>> I managed to reproduce it with the rootfs.cpio that I got some time ago from linuxppc github Wiki.
> 
> OK.
> 
> I'm using the ppc-rootfs.cpio.gz from here:
> 
>    https://github.com/linuxppc/ci-scripts/blob/master/root-disks/Makefile
> 
> And the boot script is:
> 
>    https://github.com/linuxppc/ci-scripts/blob/master/scripts/boot/qemu-mac99
> 
> I've been meaning to write docs on how to use those scripts, but haven't
> got around to it.
> 
> There's nothing really special though it's just a wrapper around qemu -M mac99.
> 
>> I'll investigate it tomorrow.
> 

Problem is the fast_interrupt_return, registers are not all saved yet on ppc32 (msr, nip, xer, ctr), 
can't restore them all as ppc64 do.

The problem happens only when userspace uses floating point or altivec.

For the time being, I'll keep the original fast_interrupt_return.

I will likely send a new version of the series later today, taking into account Nick's comments.

Christophe

^ permalink raw reply

* Re: [PATCH v2 40/43] powerpc/64s: Make kuap_check_amr() and kuap_get_and_check_amr() generic
From: Christophe Leroy @ 2021-03-12  8:37 UTC (permalink / raw)
  To: Nicholas Piggin, Benjamin Herrenschmidt, Michael Ellerman,
	Paul Mackerras
  Cc: linuxppc-dev, linux-kernel
In-Reply-To: <1615340152.vcj9lsklbx.astroid@bobo.none>



Le 10/03/2021 à 02:37, Nicholas Piggin a écrit :
> Excerpts from Christophe Leroy's message of March 9, 2021 10:10 pm:
>> In preparation of porting powerpc32 to C syscall entry/exit,
>> rename kuap_check_amr() and kuap_get_and_check_amr() as kuap_check()
>> and kuap_get_and_check(), and move in the generic asm/kup.h the stub
>> for when CONFIG_PPC_KUAP is not selected.
> 
> Looks pretty straightforward to me.
> 
> While you're renaming things, could kuap_check_amr() be changed to
> kuap_assert_locked() or similar? Otherwise,

Ok, renamed kuap_assert_locked() and kuap_get_and_assert_locked()

> 
> Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
> 
>>
>> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
>> ---
>>   arch/powerpc/include/asm/book3s/64/kup.h | 24 ++----------------------
>>   arch/powerpc/include/asm/kup.h           | 10 +++++++++-
>>   arch/powerpc/kernel/interrupt.c          | 12 ++++++------
>>   arch/powerpc/kernel/irq.c                |  2 +-
>>   4 files changed, 18 insertions(+), 30 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/book3s/64/kup.h b/arch/powerpc/include/asm/book3s/64/kup.h
>> index 8bd905050896..d9b07e9998be 100644
>> --- a/arch/powerpc/include/asm/book3s/64/kup.h
>> +++ b/arch/powerpc/include/asm/book3s/64/kup.h
>> @@ -287,7 +287,7 @@ static inline void kuap_kernel_restore(struct pt_regs *regs,
>>   	 */
>>   }
>>   
>> -static inline unsigned long kuap_get_and_check_amr(void)
>> +static inline unsigned long kuap_get_and_check(void)
>>   {
>>   	if (mmu_has_feature(MMU_FTR_BOOK3S_KUAP)) {
>>   		unsigned long amr = mfspr(SPRN_AMR);
>> @@ -298,27 +298,7 @@ static inline unsigned long kuap_get_and_check_amr(void)
>>   	return 0;
>>   }
>>   
>> -#else /* CONFIG_PPC_PKEY */
>> -
>> -static inline void kuap_user_restore(struct pt_regs *regs)
>> -{
>> -}
>> -
>> -static inline void kuap_kernel_restore(struct pt_regs *regs, unsigned long amr)
>> -{
>> -}
>> -
>> -static inline unsigned long kuap_get_and_check_amr(void)
>> -{
>> -	return 0;
>> -}
>> -
>> -#endif /* CONFIG_PPC_PKEY */
>> -
>> -
>> -#ifdef CONFIG_PPC_KUAP
>> -
>> -static inline void kuap_check_amr(void)
>> +static inline void kuap_check(void)
>>   {
>>   	if (IS_ENABLED(CONFIG_PPC_KUAP_DEBUG) && mmu_has_feature(MMU_FTR_BOOK3S_KUAP))
>>   		WARN_ON_ONCE(mfspr(SPRN_AMR) != AMR_KUAP_BLOCKED);
>> diff --git a/arch/powerpc/include/asm/kup.h b/arch/powerpc/include/asm/kup.h
>> index 25671f711ec2..b7efa46b3109 100644
>> --- a/arch/powerpc/include/asm/kup.h
>> +++ b/arch/powerpc/include/asm/kup.h
>> @@ -74,7 +74,15 @@ bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
>>   	return false;
>>   }
>>   
>> -static inline void kuap_check_amr(void) { }
>> +static inline void kuap_check(void) { }
>> +static inline void kuap_save_and_lock(struct pt_regs *regs) { }
>> +static inline void kuap_user_restore(struct pt_regs *regs) { }
>> +static inline void kuap_kernel_restore(struct pt_regs *regs, unsigned long amr) { }
>> +
>> +static inline unsigned long kuap_get_and_check(void)
>> +{
>> +	return 0;
>> +}
>>   
>>   /*
>>    * book3s/64/kup-radix.h defines these functions for the !KUAP case to flush
>> diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c
>> index 727b7848c9cc..40ed55064e54 100644
>> --- a/arch/powerpc/kernel/interrupt.c
>> +++ b/arch/powerpc/kernel/interrupt.c
>> @@ -76,7 +76,7 @@ notrace long system_call_exception(long r3, long r4, long r5,
>>   	} else
>>   #endif
>>   #ifdef CONFIG_PPC64
>> -		kuap_check_amr();
>> +		kuap_check();
>>   #endif
>>   
>>   	booke_restore_dbcr0();
>> @@ -254,7 +254,7 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3,
>>   	CT_WARN_ON(ct_state() == CONTEXT_USER);
>>   
>>   #ifdef CONFIG_PPC64
>> -	kuap_check_amr();
>> +	kuap_check();
>>   #endif
>>   
>>   	regs->result = r3;
>> @@ -380,7 +380,7 @@ notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned
>>   	 * AMR can only have been unlocked if we interrupted the kernel.
>>   	 */
>>   #ifdef CONFIG_PPC64
>> -	kuap_check_amr();
>> +	kuap_check();
>>   #endif
>>   
>>   	local_irq_save(flags);
>> @@ -451,7 +451,7 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsign
>>   	unsigned long flags;
>>   	unsigned long ret = 0;
>>   #ifdef CONFIG_PPC64
>> -	unsigned long amr;
>> +	unsigned long kuap;
>>   #endif
>>   
>>   	if (!IS_ENABLED(CONFIG_BOOKE) && !IS_ENABLED(CONFIG_40x) &&
>> @@ -467,7 +467,7 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsign
>>   		CT_WARN_ON(ct_state() == CONTEXT_USER);
>>   
>>   #ifdef CONFIG_PPC64
>> -	amr = kuap_get_and_check_amr();
>> +	kuap = kuap_get_and_check();
>>   #endif
>>   
>>   	if (unlikely(current_thread_info()->flags & _TIF_EMULATE_STACK_STORE)) {
>> @@ -511,7 +511,7 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsign
>>   	 * value from the check above.
>>   	 */
>>   #ifdef CONFIG_PPC64
>> -	kuap_kernel_restore(regs, amr);
>> +	kuap_kernel_restore(regs, kuap);
>>   #endif
>>   
>>   	return ret;
>> diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
>> index d71fd10a1dd4..3b18d2b2c702 100644
>> --- a/arch/powerpc/kernel/irq.c
>> +++ b/arch/powerpc/kernel/irq.c
>> @@ -282,7 +282,7 @@ static inline void replay_soft_interrupts_irqrestore(void)
>>   	 * and re-locking AMR but we shouldn't get here in the first place,
>>   	 * hence the warning.
>>   	 */
>> -	kuap_check_amr();
>> +	kuap_check();
>>   
>>   	if (kuap_state != AMR_KUAP_BLOCKED)
>>   		set_kuap(AMR_KUAP_BLOCKED);
>> -- 
>> 2.25.0
>>
>>

^ permalink raw reply

* Re: [PATCH v2 28/43] powerpc/64e: Call bad_page_fault() from do_page_fault()
From: Christophe Leroy @ 2021-03-12  8:39 UTC (permalink / raw)
  To: Nicholas Piggin, Benjamin Herrenschmidt, Michael Ellerman,
	Paul Mackerras
  Cc: linuxppc-dev, linux-kernel
In-Reply-To: <1615339667.i88ve15v8a.astroid@bobo.none>



Le 10/03/2021 à 02:29, Nicholas Piggin a écrit :
> Excerpts from Christophe Leroy's message of March 9, 2021 10:09 pm:
>> book3e/64 is the last one calling __bad_page_fault()
>> from assembly.
>>
>> Save non volatile registers before calling do_page_fault()
>> and modify do_page_fault() to call __bad_page_fault()
>> for all platforms.
>>
>> Then it can be refactored by the call of bad_page_fault()
>> which avoids the duplication of the exception table search.
> 
> This can go in with the 64e change after your series. I think it should
> be ready for the next merge window as well.

Yes, I thought it would pull more optimisation, but at the end it doesn't bring anythink, so I'll 
drop it for now and leave it to you for your series.

> 
> Thanks,
> Nick
> 
>>
>> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
>> ---
>>   arch/powerpc/kernel/exceptions-64e.S |  8 +-------
>>   arch/powerpc/mm/fault.c              | 17 ++++-------------
>>   2 files changed, 5 insertions(+), 20 deletions(-)
>>
>> diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S
>> index e8eb9992a270..b60f89078a3f 100644
>> --- a/arch/powerpc/kernel/exceptions-64e.S
>> +++ b/arch/powerpc/kernel/exceptions-64e.S
>> @@ -1010,15 +1010,9 @@ storage_fault_common:
>>   	addi	r3,r1,STACK_FRAME_OVERHEAD
>>   	ld	r14,PACA_EXGEN+EX_R14(r13)
>>   	ld	r15,PACA_EXGEN+EX_R15(r13)
>> +	bl	save_nvgprs
>>   	bl	do_page_fault
>> -	cmpdi	r3,0
>> -	bne-	1f
>>   	b	ret_from_except_lite
>> -1:	bl	save_nvgprs
>> -	mr	r4,r3
>> -	addi	r3,r1,STACK_FRAME_OVERHEAD
>> -	bl	__bad_page_fault
>> -	b	ret_from_except
>>   
>>   /*
>>    * Alignment exception doesn't fit entirely in the 0x100 bytes so it
>> diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
>> index 2e54bac99a22..7bcff3fca110 100644
>> --- a/arch/powerpc/mm/fault.c
>> +++ b/arch/powerpc/mm/fault.c
>> @@ -541,24 +541,15 @@ NOKPROBE_SYMBOL(___do_page_fault);
>>   
>>   static long __do_page_fault(struct pt_regs *regs)
>>   {
>> -	const struct exception_table_entry *entry;
>>   	long err;
>>   
>>   	err = ___do_page_fault(regs, regs->dar, regs->dsisr);
>>   	if (likely(!err))
>> -		return err;
>> -
>> -	entry = search_exception_tables(regs->nip);
>> -	if (likely(entry)) {
>> -		instruction_pointer_set(regs, extable_fixup(entry));
>>   		return 0;
>> -	} else if (!IS_ENABLED(CONFIG_PPC_BOOK3E_64)) {
>> -		__bad_page_fault(regs, err);
>> -		return 0;
>> -	} else {
>> -		/* 32 and 64e handle the bad page fault in asm */
>> -		return err;
>> -	}
>> +
>> +	bad_page_fault(regs, err);
>> +
>> +	return 0;
>>   }
>>   NOKPROBE_SYMBOL(__do_page_fault);
>>   
>> -- 
>> 2.25.0
>>
>>

^ permalink raw reply

* Re: [PATCH v2 02/43] powerpc/traps: Declare unrecoverable_exception() as __noreturn
From: Christophe Leroy @ 2021-03-12  8:40 UTC (permalink / raw)
  To: Nicholas Piggin, Benjamin Herrenschmidt, Michael Ellerman,
	Paul Mackerras
  Cc: linuxppc-dev, linux-kernel
In-Reply-To: <1615339022.cb2m6h66vl.astroid@bobo.none>



Le 10/03/2021 à 02:22, Nicholas Piggin a écrit :
> Excerpts from Christophe Leroy's message of March 9, 2021 10:09 pm:
>> unrecoverable_exception() is never expected to return, most callers
>> have an infiniteloop in case it returns.
>>
>> Ensure it really never returns by terminating it with a BUG(), and
>> declare it __no_return.
>>
>> It always GCC to really simplify functions calling it. In the exemple
>> below, it avoids the stack frame in the likely fast path and avoids
>> code duplication for the exit.
>>
>> With this patch:
> 
> [snip]
> 
> Nice.
> 
>> diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
>> index a44a30b0688c..d5c9d9ddd186 100644
>> --- a/arch/powerpc/kernel/traps.c
>> +++ b/arch/powerpc/kernel/traps.c
>> @@ -2170,11 +2170,15 @@ DEFINE_INTERRUPT_HANDLER(SPEFloatingPointRoundException)
>>    * in the MSR is 0.  This indicates that SRR0/1 are live, and that
>>    * we therefore lost state by taking this exception.
>>    */
>> -void unrecoverable_exception(struct pt_regs *regs)
>> +void __noreturn unrecoverable_exception(struct pt_regs *regs)
>>   {
>>   	pr_emerg("Unrecoverable exception %lx at %lx (msr=%lx)\n",
>>   		 regs->trap, regs->nip, regs->msr);
>>   	die("Unrecoverable exception", regs, SIGABRT);
>> +	/* die() should not return */
>> +	WARN(true, "die() unexpectedly returned");
>> +	for (;;)
>> +		;
>>   }
> 
> I don't think the WARN should be added because that will cause another
> interrupt after something is already badly wrong, so this might just
> make it harder to debug.
> 
> For example if die() is falling through for some reason, we warn and
> cause a program check here, and that might also be unrecoverable so it
> might come through here and fall through again and warn again, etc.
> 
> Putting the infinite loop is good enough I think (and better than there
> was previously).

Ok, dropped the WARN()

> 
> Otherwise
> 
> Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
> 
> Thanks,
> Nick
> 

^ permalink raw reply

* [PATCH v6] soc: fsl: enable acpi support in RCPM driver
From: Ran Wang @ 2021-03-12  8:58 UTC (permalink / raw)
  To: Li Yang, Christophe Leroy
  Cc: Peng Ma, Ran Wang, linuxppc-dev, linux-kernel, linux-arm-kernel

From: Peng Ma <peng.ma@nxp.com>

This patch enables ACPI support in RCPM driver.

Signed-off-by: Peng Ma <peng.ma@nxp.com>
Signed-off-by: Ran Wang <ran.wang_1@nxp.com>
---
Change in v6:
 - Remove copyright udpate to rebase on latest mainline

Change in v5:
 - Fix panic when dev->of_node is null

Change in v4:
 - Make commit subject more accurate
 - Remove unrelated new blank line

Change in v3:
 - Add #ifdef CONFIG_ACPI for acpi_device_id
 - Rename rcpm_acpi_imx_ids to rcpm_acpi_ids

Change in v2:
 - Update acpi_device_id to fix conflict with other driver

 drivers/soc/fsl/rcpm.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/soc/fsl/rcpm.c b/drivers/soc/fsl/rcpm.c
index 4ace28cab314..7aa997b932d1 100644
--- a/drivers/soc/fsl/rcpm.c
+++ b/drivers/soc/fsl/rcpm.c
@@ -13,6 +13,7 @@
 #include <linux/slab.h>
 #include <linux/suspend.h>
 #include <linux/kernel.h>
+#include <linux/acpi.h>
 
 #define RCPM_WAKEUP_CELL_MAX_SIZE	7
 
@@ -78,10 +79,14 @@ static int rcpm_pm_prepare(struct device *dev)
 				"fsl,rcpm-wakeup", value,
 				rcpm->wakeup_cells + 1);
 
-		/*  Wakeup source should refer to current rcpm device */
-		if (ret || (np->phandle != value[0]))
+		if (ret)
 			continue;
 
+		if (is_of_node(dev->fwnode))
+			/*  Should refer to current rcpm device */
+			if (np->phandle != value[0])
+				continue;
+
 		/* Property "#fsl,rcpm-wakeup-cells" of rcpm node defines the
 		 * number of IPPDEXPCR register cells, and "fsl,rcpm-wakeup"
 		 * of wakeup source IP contains an integer array: <phandle to
@@ -172,10 +177,19 @@ static const struct of_device_id rcpm_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, rcpm_of_match);
 
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id rcpm_acpi_ids[] = {
+	{"NXP0015",},
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, rcpm_acpi_ids);
+#endif
+
 static struct platform_driver rcpm_driver = {
 	.driver = {
 		.name = "rcpm",
 		.of_match_table = rcpm_of_match,
+		.acpi_match_table = ACPI_PTR(rcpm_acpi_ids),
 		.pm	= &rcpm_pm_ops,
 	},
 	.probe = rcpm_probe,
-- 
2.25.1


^ permalink raw reply related

* [PATCH] powerpc: memblock alloc fixes
From: Youlin Song @ 2021-03-12  9:07 UTC (permalink / raw)
  To: mpe, benh, paulus, christophe.leroy, aneesh.kumar
  Cc: Youlin Song, linuxppc-dev, linux-kernel

If the memory starts at 64MB physical address,the memblock
will not be allocated.Because it was in the range of 0~64M
(according to TLB) to alloc when the system was started,
but the memblock calculates whether it is in this space
based on the actual physical address(offset 64M).

Signed-off-by: Youlin Song <syl.loop@gmail.com>
---
 arch/powerpc/kernel/prom.c         | 2 ++
 arch/powerpc/mm/nohash/fsl_booke.c | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 9a4797d1d40d..addc05c6f8ff 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -785,6 +785,8 @@ void __init early_init_devtree(void *params)
 
 	DBG("Phys. mem: %llx\n", (unsigned long long)memblock_phys_mem_size());
 
+	memblock_set_bottom_up(true);
+
 	/* We may need to relocate the flat tree, do it now.
 	 * FIXME .. and the initrd too? */
 	move_device_tree();
diff --git a/arch/powerpc/mm/nohash/fsl_booke.c b/arch/powerpc/mm/nohash/fsl_booke.c
index 03dacbe940e5..f6f36e78ec41 100644
--- a/arch/powerpc/mm/nohash/fsl_booke.c
+++ b/arch/powerpc/mm/nohash/fsl_booke.c
@@ -264,7 +264,7 @@ void setup_initial_memory_limit(phys_addr_t first_memblock_base,
 	phys_addr_t limit = first_memblock_base + first_memblock_size;
 
 	/* 64M mapped initially according to head_fsl_booke.S */
-	memblock_set_current_limit(min_t(u64, limit, 0x04000000));
+	memblock_set_current_limit(min_t(u64, limit, first_memblock_base + 0x04000000));
 }
 
 #ifdef CONFIG_RELOCATABLE
-- 
2.25.1


^ permalink raw reply related

* RE: Errant readings on LM81 with T2080 SoC
From: David Laight @ 2021-03-12  9:25 UTC (permalink / raw)
  To: 'Guenter Roeck', Chris Packham, Wolfram Sang
  Cc: linux-hwmon@vger.kernel.org, jdelvare@suse.com,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	linux-i2c@vger.kernel.org
In-Reply-To: <725c5e51-65df-e17d-e2da-0982efacf2d2@roeck-us.net>

From: Linuxppc-dev Guenter Roeck
> Sent: 11 March 2021 21:35
> 
> On 3/11/21 1:17 PM, Chris Packham wrote:
> >
> > On 11/03/21 9:18 pm, Wolfram Sang wrote:
> >>> Bummer. What is really weird is that you see clock stretching under
> >>> CPU load. Normally clock stretching is triggered by the device, not
> >>> by the host.
> >> One example: Some hosts need an interrupt per byte to know if they
> >> should send ACK or NACK. If that interrupt is delayed, they stretch the
> >> clock.
> >>
> > It feels like something like that is happening. Looking at the T2080
> > Reference manual there is an interesting timing diagram (Figure 14-2 if
> > someone feels like looking it up). It shows SCL low between the ACK for
> > the address and the data byte. I think if we're delayed in sending the
> > next byte we could violate Ttimeout or Tlow:mext from the SMBUS spec.
> >
> 
> I think that really leaves you only two options that I can see:
> Rework the driver to handle critical actions (such as setting TXAK,
> and everything else that might result in clock stretching) in the
> interrupt handler, or rework the driver to handle everything in
> a high priority kernel thread.

I'm not sure a high priority kernel thread will help.
Without CONFIG_PREEMPT (which has its own set of nasties)
a RT process won't be scheduled until the processor it last
ran on does a reschedule.
I don't think a kernel thread will be any different from a
user process running under the RT scheduler.

I'm trying to remember the smbus spec (without remembering the I2C one).
While basically a clock+data bit-bang the slave is allowed to drive
the clock low to extend a cycle.
It may be allowed to do this at any point?
The master can generate the data at almost any rate (below the maximum)
but I don't think it can go down to zero.
But I do remember one of the specs having a timeout.

But I'd have thought the slave should answer the cycle correctly
regardless of any 'random' delays the master adds in.
Unless you are getting away with de-asserting chipselect?

The only implementation I've done is one an FPGA so doesn't have
worry about interrupt latencies.
It doesn't actually support clock stretching; it wasn't in the
code I started from and none of the slaves we need to connect to
ever does it.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)


^ permalink raw reply

* Re: [PATCH] [backport for 5.10] powerpc/603: Fix protection of user pages mapped with PROT_NONE
From: Greg KH @ 2021-03-12 10:03 UTC (permalink / raw)
  To: Christophe Leroy; +Cc: linuxppc-dev, linux-kernel, stable
In-Reply-To: <656520fecf792b8842dc54beec2da3bc29d0133c.1615486986.git.christophe.leroy@csgroup.eu>

On Thu, Mar 11, 2021 at 06:24:30PM +0000, Christophe Leroy wrote:
> (cherry picked from commit c119565a15a628efdfa51352f9f6c5186e506a1c)
> 
> On book3s/32, page protection is defined by the PP bits in the PTE
> which provide the following protection depending on the access
> keys defined in the matching segment register:
> - PP 00 means RW with key 0 and N/A with key 1.
> - PP 01 means RW with key 0 and RO with key 1.
> - PP 10 means RW with both key 0 and key 1.
> - PP 11 means RO with both key 0 and key 1.
> 
> Since the implementation of kernel userspace access protection,
> PP bits have been set as follows:
> - PP00 for pages without _PAGE_USER
> - PP01 for pages with _PAGE_USER and _PAGE_RW
> - PP11 for pages with _PAGE_USER and without _PAGE_RW
> 
> For kernelspace segments, kernel accesses are performed with key 0
> and user accesses are performed with key 1. As PP00 is used for
> non _PAGE_USER pages, user can't access kernel pages not flagged
> _PAGE_USER while kernel can.
> 
> For userspace segments, both kernel and user accesses are performed
> with key 0, therefore pages not flagged _PAGE_USER are still
> accessible to the user.
> 
> This shouldn't be an issue, because userspace is expected to be
> accessible to the user. But unlike most other architectures, powerpc
> implements PROT_NONE protection by removing _PAGE_USER flag instead of
> flagging the page as not valid. This means that pages in userspace
> that are not flagged _PAGE_USER shall remain inaccessible.
> 
> To get the expected behaviour, just mimic other architectures in the
> TLB miss handler by checking _PAGE_USER permission on userspace
> accesses as if it was the _PAGE_PRESENT bit.
> 
> Note that this problem only is only for 603 cores. The 604+ have
> an hash table, and hash_page() function already implement the
> verification of _PAGE_USER permission on userspace pages.
> 
> Fixes: f342adca3afc ("powerpc/32s: Prepare Kernel Userspace Access Protection")
> Change-Id: I68bc5e5ff4542bdfcdcd12923fa96a5811707475
> Cc: stable@vger.kernel.org # v5.2+
> Reported-by: Christoph Plattner <christoph.plattner@thalesgroup.com>
> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
> Link: https://lore.kernel.org/r/4a0c6e3bb8f0c162457bf54d9bc6fd8d7b55129f.1612160907.git.christophe.leroy@csgroup.eu
> ---
>  arch/powerpc/kernel/head_book3s_32.S | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)

Both backports applied, thanks.

greg k-h

^ permalink raw reply

* Re: [PATCH v2 1/8] powerpc/xive: Use cpu_to_node() instead of ibm,chip-id property
From: Cédric Le Goater @ 2021-03-12  9:53 UTC (permalink / raw)
  To: David Gibson
  Cc: Daniel Henrique Barboza, Greg Kurz, QEMU Developers,
	list@suse.de:PowerPC, linuxppc-dev
In-Reply-To: <20210312125527.61bc269c@yekko.fritz.box>

On 3/12/21 2:55 AM, David Gibson wrote:
> On Tue, 9 Mar 2021 18:26:35 +0100
> Cédric Le Goater <clg@kaod.org> wrote:
> 
>> On 3/9/21 6:08 PM, Daniel Henrique Barboza wrote:
>>>
>>>
>>> On 3/9/21 12:33 PM, Cédric Le Goater wrote:  
>>>> On 3/8/21 6:13 PM, Greg Kurz wrote:  
>>>>> On Wed, 3 Mar 2021 18:48:50 +0100
>>>>> Cédric Le Goater <clg@kaod.org> wrote:
>>>>>  
>>>>>> The 'chip_id' field of the XIVE CPU structure is used to choose a
>>>>>> target for a source located on the same chip when possible. This field
>>>>>> is assigned on the PowerNV platform using the "ibm,chip-id" property
>>>>>> on pSeries under KVM when NUMA nodes are defined but it is undefined  
>>>>>
>>>>> This sentence seems to have a syntax problem... like it is missing an
>>>>> 'and' before 'on pSeries'.  
>>>>
>>>> ah yes, or simply a comma.
>>>>  
>>>>>> under PowerVM. The XIVE source structure has a similar field
>>>>>> 'src_chip' which is only assigned on the PowerNV platform.
>>>>>>
>>>>>> cpu_to_node() returns a compatible value on all platforms, 0 being the
>>>>>> default node. It will also give us the opportunity to set the affinity
>>>>>> of a source on pSeries when we can localize them.
>>>>>>  
>>>>>
>>>>> IIUC this relies on the fact that the NUMA node id is == to chip id
>>>>> on PowerNV, i.e. xc->chip_id which is passed to OPAL remain stable
>>>>> with this change.  
>>>>
>>>> Linux sets the NUMA node in numa_setup_cpu(). On pseries, the hcall
>>>> H_HOME_NODE_ASSOCIATIVITY returns the node id if I am correct (Daniel
>>>> in Cc:)  
>>  [...]  
>>>>
>>>> On PowerNV, Linux uses "ibm,associativity" property of the CPU to find
>>>> the node id. This value is built from the chip id in OPAL, so the
>>>> value returned by cpu_to_node(cpu) and the value of the "ibm,chip-id"
>>>> property are unlikely to be different.
>>>>
>>>> cpu_to_node(cpu) is used in many places to allocate the structures
>>>> locally to the owning node. XIVE is not an exception (see below in the
>>>> same patch), it is better to be consistent and get the same information
>>>> (node id) using the same routine.
>>>>
>>>>
>>>> In Linux, "ibm,chip-id" is only used in low level PowerNV drivers :
>>>> LPC, XSCOM, RNG, VAS, NX. XIVE should be in that list also but skiboot
>>>> unifies the controllers of the system to only expose one the OS. This
>>>> is problematic and should be changed but it's another topic.
>>>>
>>>>  
>>>>> On the other hand, you have the pSeries case under PowerVM that
>>>>> doesn't xc->chip_id, which isn't passed to any hcall AFAICT.  
>>>>
>>>> yes "ibm,chip-id" is an OPAL concept unfortunately and it has no meaning
>>>> under PAPR. xc->chip_id on pseries (PowerVM) will contains an invalid
>>>> chip id.
>>>>
>>>> QEMU/KVM exposes "ibm,chip-id" but it's not used. (its value is not
>>>> always correct btw)  
>>>
>>>
>>> If you have a way to reliably reproduce this, let me know and I'll fix it
>>> up in QEMU.  
>>
>> with :
>>
>>    -smp 4,cores=1,maxcpus=8 -object memory-backend-ram,id=ram-node0,size=2G -numa node,nodeid=0,cpus=0-1,cpus=4-5,memdev=ram-node0 -object memory-backend-ram,id=ram-node1,size=2G -numa node,nodeid=1,cpus=2-3,cpus=6-7,memdev=ram-node1
>>
>> # dmesg | grep numa
>> [    0.013106] numa: Node 0 CPUs: 0-1
>> [    0.013136] numa: Node 1 CPUs: 2-3
>>
>> # dtc -I fs /proc/device-tree/cpus/ -f | grep ibm,chip-id
>> 		ibm,chip-id = <0x01>;
>> 		ibm,chip-id = <0x02>;
>> 		ibm,chip-id = <0x00>;
>> 		ibm,chip-id = <0x03>;
>>
>> with :
>>
>>   -smp 4,cores=4,maxcpus=8,threads=1 -object memory-backend-ram,id=ram-node0,size=2G -numa node,nodeid=0,cpus=0-1,cpus=4-5,memdev=ram-node0 -object memory-backend-ram,id=ram-node1,size=2G -numa node,nodeid=1,cpus=2-3,cpus=6-7,memdev=ram-node1
>>
>> # dmesg | grep numa
>> [    0.013106] numa: Node 0 CPUs: 0-1
>> [    0.013136] numa: Node 1 CPUs: 2-3
>>
>> # dtc -I fs /proc/device-tree/cpus/ -f | grep ibm,chip-id
>> 		ibm,chip-id = <0x00>;
>> 		ibm,chip-id = <0x00>;
>> 		ibm,chip-id = <0x00>;
>> 		ibm,chip-id = <0x00>;
>>
>> I think we should simply remove "ibm,chip-id" since it's not used and
>> not in the PAPR spec.
> 
> As I mentioned to Daniel on our call this morning, oddly it *does*
> appear to be used in the RHEL kernel, even though that's 4.18 based.
> This patch seems to have caused a minor regression; not in the
> identification of NUMA nodes, but in the number of sockets shown be
> lscpu, etc.  See https://bugzilla.redhat.com/show_bug.cgi?id=1934421
> for more information.

Yes. The property "ibm,chip-id" is wrongly calculated in QEMU. If we 
remove it, we get with 4.18.0-295.el8.ppc64le or 5.12.0-rc2 :

   [root@localhost ~]# lscpu 
   Architecture:        ppc64le
   Byte Order:          Little Endian
   CPU(s):              128
   On-line CPU(s) list: 0-127
   Thread(s) per core:  4
   Core(s) per socket:  16
   Socket(s):           2
   NUMA node(s):        2
   Model:               2.2 (pvr 004e 1202)
   Model name:          POWER9 (architected), altivec supported
   Hypervisor vendor:   KVM
   Virtualization type: para
   L1d cache:           32K
   L1i cache:           32K
   NUMA node0 CPU(s):   0-63
   NUMA node1 CPU(s):   64-127

   [root@localhost ~]# grep . /sys/devices/system/cpu/*/topology/physical_package_id
   /sys/devices/system/cpu/cpu0/topology/physical_package_id:-1
   /sys/devices/system/cpu/cpu100/topology/physical_package_id:-1
   /sys/devices/system/cpu/cpu101/topology/physical_package_id:-1
   /sys/devices/system/cpu/cpu102/topology/physical_package_id:-1
   /sys/devices/system/cpu/cpu103/topology/physical_package_id:-1
   ....

"ibm,chip-id" is still being used on some occasion on pSeries machines.
This is wrong :/ The problem is :

  #define topology_physical_package_id(cpu)      (cpu_to_chip_id(cpu))

We should be using cpu_to_node(). 

C.

> 
> Since the value was used by some PAPR kernels - even if they shouldn't
> have - I think we should only remove this for newer machine types.  We
> also need to check what we're not supplying that the guest kernel is
> showing a different number of sockets than specified on the qemu
> command line.
> 
>>
>> Thanks,
>>
>> C.
>>
>>  
>>
>>  [...]  
>>  [...]  
>>  [...]  
>>  [...]  
>>  [...]  
>>  [...]  
>>  [...]  
>>  [...]  
>>  [...]  
>>
> 
> 


^ permalink raw reply

* [PATCH] powerpc: mm: book3s64: Fix a typo in the file mmu_context.c
From: Bhaskar Chowdhury @ 2021-03-12 11:25 UTC (permalink / raw)
  To: mpe, benh, paulus, npiggin, unixbhaskar, aneesh.kumar,
	linuxppc-dev, linux-kernel
  Cc: rdunlap


s/detalis/details/

Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
---
 arch/powerpc/mm/book3s64/mmu_context.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/mm/book3s64/mmu_context.c b/arch/powerpc/mm/book3s64/mmu_context.c
index 0c8557220ae2..c10fc8a72fb3 100644
--- a/arch/powerpc/mm/book3s64/mmu_context.c
+++ b/arch/powerpc/mm/book3s64/mmu_context.c
@@ -119,7 +119,7 @@ static int hash__init_new_context(struct mm_struct *mm)
 		/* This is fork. Copy hash_context details from current->mm */
 		memcpy(mm->context.hash_context, current->mm->context.hash_context, sizeof(struct hash_mm_context));
 #ifdef CONFIG_PPC_SUBPAGE_PROT
-		/* inherit subpage prot detalis if we have one. */
+		/* inherit subpage prot details if we have one. */
 		if (current->mm->context.hash_context->spt) {
 			mm->context.hash_context->spt = kmalloc(sizeof(struct subpage_prot_table),
 								GFP_KERNEL);
--
2.26.2


^ permalink raw reply related

* Re: [PATCH v2 1/8] powerpc/xive: Use cpu_to_node() instead of ibm,chip-id property
From: Daniel Henrique Barboza @ 2021-03-12 12:18 UTC (permalink / raw)
  To: Cédric Le Goater, David Gibson
  Cc: list@suse.de:PowerPC, linuxppc-dev, Greg Kurz, QEMU Developers
In-Reply-To: <4effbb5e-6f08-03bf-cea0-60c986175668@kaod.org>



On 3/12/21 6:53 AM, Cédric Le Goater wrote:
> On 3/12/21 2:55 AM, David Gibson wrote:
>> On Tue, 9 Mar 2021 18:26:35 +0100
>> Cédric Le Goater <clg@kaod.org> wrote:
>>
>>> On 3/9/21 6:08 PM, Daniel Henrique Barboza wrote:
>>>>
>>>>
>>>> On 3/9/21 12:33 PM, Cédric Le Goater wrote:
>>>>> On 3/8/21 6:13 PM, Greg Kurz wrote:
>>>>>> On Wed, 3 Mar 2021 18:48:50 +0100
>>>>>> Cédric Le Goater <clg@kaod.org> wrote:
>>>>>>   
>>>>>>> The 'chip_id' field of the XIVE CPU structure is used to choose a
>>>>>>> target for a source located on the same chip when possible. This field
>>>>>>> is assigned on the PowerNV platform using the "ibm,chip-id" property
>>>>>>> on pSeries under KVM when NUMA nodes are defined but it is undefined
>>>>>>
>>>>>> This sentence seems to have a syntax problem... like it is missing an
>>>>>> 'and' before 'on pSeries'.
>>>>>
>>>>> ah yes, or simply a comma.
>>>>>   
>>>>>>> under PowerVM. The XIVE source structure has a similar field
>>>>>>> 'src_chip' which is only assigned on the PowerNV platform.
>>>>>>>
>>>>>>> cpu_to_node() returns a compatible value on all platforms, 0 being the
>>>>>>> default node. It will also give us the opportunity to set the affinity
>>>>>>> of a source on pSeries when we can localize them.
>>>>>>>   
>>>>>>
>>>>>> IIUC this relies on the fact that the NUMA node id is == to chip id
>>>>>> on PowerNV, i.e. xc->chip_id which is passed to OPAL remain stable
>>>>>> with this change.
>>>>>
>>>>> Linux sets the NUMA node in numa_setup_cpu(). On pseries, the hcall
>>>>> H_HOME_NODE_ASSOCIATIVITY returns the node id if I am correct (Daniel
>>>>> in Cc:)
>>>   [...]
>>>>>
>>>>> On PowerNV, Linux uses "ibm,associativity" property of the CPU to find
>>>>> the node id. This value is built from the chip id in OPAL, so the
>>>>> value returned by cpu_to_node(cpu) and the value of the "ibm,chip-id"
>>>>> property are unlikely to be different.
>>>>>
>>>>> cpu_to_node(cpu) is used in many places to allocate the structures
>>>>> locally to the owning node. XIVE is not an exception (see below in the
>>>>> same patch), it is better to be consistent and get the same information
>>>>> (node id) using the same routine.
>>>>>
>>>>>
>>>>> In Linux, "ibm,chip-id" is only used in low level PowerNV drivers :
>>>>> LPC, XSCOM, RNG, VAS, NX. XIVE should be in that list also but skiboot
>>>>> unifies the controllers of the system to only expose one the OS. This
>>>>> is problematic and should be changed but it's another topic.
>>>>>
>>>>>   
>>>>>> On the other hand, you have the pSeries case under PowerVM that
>>>>>> doesn't xc->chip_id, which isn't passed to any hcall AFAICT.
>>>>>
>>>>> yes "ibm,chip-id" is an OPAL concept unfortunately and it has no meaning
>>>>> under PAPR. xc->chip_id on pseries (PowerVM) will contains an invalid
>>>>> chip id.
>>>>>
>>>>> QEMU/KVM exposes "ibm,chip-id" but it's not used. (its value is not
>>>>> always correct btw)
>>>>
>>>>
>>>> If you have a way to reliably reproduce this, let me know and I'll fix it
>>>> up in QEMU.
>>>
>>> with :
>>>
>>>     -smp 4,cores=1,maxcpus=8 -object memory-backend-ram,id=ram-node0,size=2G -numa node,nodeid=0,cpus=0-1,cpus=4-5,memdev=ram-node0 -object memory-backend-ram,id=ram-node1,size=2G -numa node,nodeid=1,cpus=2-3,cpus=6-7,memdev=ram-node1
>>>
>>> # dmesg | grep numa
>>> [    0.013106] numa: Node 0 CPUs: 0-1
>>> [    0.013136] numa: Node 1 CPUs: 2-3
>>>
>>> # dtc -I fs /proc/device-tree/cpus/ -f | grep ibm,chip-id
>>> 		ibm,chip-id = <0x01>;
>>> 		ibm,chip-id = <0x02>;
>>> 		ibm,chip-id = <0x00>;
>>> 		ibm,chip-id = <0x03>;
>>>
>>> with :
>>>
>>>    -smp 4,cores=4,maxcpus=8,threads=1 -object memory-backend-ram,id=ram-node0,size=2G -numa node,nodeid=0,cpus=0-1,cpus=4-5,memdev=ram-node0 -object memory-backend-ram,id=ram-node1,size=2G -numa node,nodeid=1,cpus=2-3,cpus=6-7,memdev=ram-node1
>>>
>>> # dmesg | grep numa
>>> [    0.013106] numa: Node 0 CPUs: 0-1
>>> [    0.013136] numa: Node 1 CPUs: 2-3
>>>
>>> # dtc -I fs /proc/device-tree/cpus/ -f | grep ibm,chip-id
>>> 		ibm,chip-id = <0x00>;
>>> 		ibm,chip-id = <0x00>;
>>> 		ibm,chip-id = <0x00>;
>>> 		ibm,chip-id = <0x00>;
>>>
>>> I think we should simply remove "ibm,chip-id" since it's not used and
>>> not in the PAPR spec.
>>
>> As I mentioned to Daniel on our call this morning, oddly it *does*
>> appear to be used in the RHEL kernel, even though that's 4.18 based.
>> This patch seems to have caused a minor regression; not in the
>> identification of NUMA nodes, but in the number of sockets shown be
>> lscpu, etc.  See https://bugzilla.redhat.com/show_bug.cgi?id=1934421
>> for more information.
> 
> Yes. The property "ibm,chip-id" is wrongly calculated in QEMU. If we
> remove it, we get with 4.18.0-295.el8.ppc64le or 5.12.0-rc2 :
> 
>     [root@localhost ~]# lscpu
>     Architecture:        ppc64le
>     Byte Order:          Little Endian
>     CPU(s):              128
>     On-line CPU(s) list: 0-127
>     Thread(s) per core:  4
>     Core(s) per socket:  16
>     Socket(s):           2
>     NUMA node(s):        2
>     Model:               2.2 (pvr 004e 1202)
>     Model name:          POWER9 (architected), altivec supported
>     Hypervisor vendor:   KVM
>     Virtualization type: para
>     L1d cache:           32K
>     L1i cache:           32K
>     NUMA node0 CPU(s):   0-63
>     NUMA node1 CPU(s):   64-127
> 
>     [root@localhost ~]# grep . /sys/devices/system/cpu/*/topology/physical_package_id
>     /sys/devices/system/cpu/cpu0/topology/physical_package_id:-1
>     /sys/devices/system/cpu/cpu100/topology/physical_package_id:-1
>     /sys/devices/system/cpu/cpu101/topology/physical_package_id:-1
>     /sys/devices/system/cpu/cpu102/topology/physical_package_id:-1
>     /sys/devices/system/cpu/cpu103/topology/physical_package_id:-1
>     ....
> 
> "ibm,chip-id" is still being used on some occasion on pSeries machines.
> This is wrong :/ The problem is :
> 
>    #define topology_physical_package_id(cpu)      (cpu_to_chip_id(cpu))
> 
> We should be using cpu_to_node().


IIUC the "real fix" then is this change you mentioned above, together with
this xive patch as well, to stop using ibm,chip-id for good in the pserie
  kernel. With these changes QEMU can remove 'ibm,chip-id' from the pseries
machine without impact. Is this correct?

If that's the case, then I believe it's ok to go forward with the QEMU side
change (just for 6.0.0 and newer machines). Or should I wait for the kernel
changes to be merged upstream first?


Thanks,


DHB


> 
> C.
> 
>>
>> Since the value was used by some PAPR kernels - even if they shouldn't
>> have - I think we should only remove this for newer machine types.  We
>> also need to check what we're not supplying that the guest kernel is
>> showing a different number of sockets than specified on the qemu
>> command line.
>>
>>>
>>> Thanks,
>>>
>>> C.
>>>
>>>   
>>>
>>>   [...]
>>>   [...]
>>>   [...]
>>>   [...]
>>>   [...]
>>>   [...]
>>>   [...]
>>>   [...]
>>>   [...]
>>>
>>
>>
> 

^ permalink raw reply

* [powerpc:merge] BUILD SUCCESS b38521e8bebde04fa31001435ed77a93f83d896e
From: kernel test robot @ 2021-03-12 12:38 UTC (permalink / raw)
  To: Michael Ellerman; +Cc: linuxppc-dev

tree/branch: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git merge
branch HEAD: b38521e8bebde04fa31001435ed77a93f83d896e  Automatic merge of 'fixes' into merge (2021-03-12 11:02)

elapsed time: 729m

configs tested: 147
configs skipped: 2

The following configs have been built successfully.
More configs may be tested in the coming days.

gcc tested configs:
arm                                 defconfig
arm64                            allyesconfig
arm64                               defconfig
arm                              allyesconfig
arm                              allmodconfig
powerpc                 mpc836x_rdk_defconfig
mips                        qi_lb60_defconfig
powerpc                     tqm8555_defconfig
openrisc                 simple_smp_defconfig
powerpc                     stx_gp3_defconfig
powerpc                      pmac32_defconfig
powerpc                     mpc512x_defconfig
powerpc                     kilauea_defconfig
powerpc                      ppc44x_defconfig
sh                        edosk7705_defconfig
nds32                            alldefconfig
powerpc                    socrates_defconfig
sh                           se7712_defconfig
arm                          collie_defconfig
riscv                               defconfig
powerpc                    ge_imp3a_defconfig
sh                             sh03_defconfig
arm                             mxs_defconfig
sh                        dreamcast_defconfig
arm                          ixp4xx_defconfig
h8300                               defconfig
arc                          axs101_defconfig
sh                   sh7724_generic_defconfig
m68k                         apollo_defconfig
arm                         lpc32xx_defconfig
m68k                          multi_defconfig
powerpc                     mpc5200_defconfig
mips                  maltasmvp_eva_defconfig
powerpc                  mpc866_ads_defconfig
powerpc                      ep88xc_defconfig
sh                        sh7763rdp_defconfig
arm                        neponset_defconfig
powerpc                      tqm8xx_defconfig
arm                       cns3420vb_defconfig
arc                        nsim_700_defconfig
powerpc                 mpc85xx_cds_defconfig
powerpc                 mpc832x_rdb_defconfig
arm64                            alldefconfig
sh                          r7785rp_defconfig
arc                           tb10x_defconfig
arm                        keystone_defconfig
arm                        trizeps4_defconfig
sparc                               defconfig
parisc                generic-64bit_defconfig
mips                          malta_defconfig
m68k                        mvme147_defconfig
powerpc                      ppc40x_defconfig
powerpc                     tqm8548_defconfig
arm                         s3c6400_defconfig
mips                        nlm_xlr_defconfig
arm                          iop32x_defconfig
sparc                       sparc32_defconfig
powerpc                 mpc836x_mds_defconfig
xtensa                generic_kc705_defconfig
powerpc                     tqm5200_defconfig
sparc                            allyesconfig
arc                        nsimosci_defconfig
ia64                             allmodconfig
ia64                                defconfig
ia64                             allyesconfig
m68k                             allmodconfig
m68k                                defconfig
m68k                             allyesconfig
nios2                               defconfig
arc                              allyesconfig
nds32                             allnoconfig
nds32                               defconfig
nios2                            allyesconfig
csky                                defconfig
alpha                               defconfig
alpha                            allyesconfig
xtensa                           allyesconfig
h8300                            allyesconfig
arc                                 defconfig
sh                               allmodconfig
parisc                              defconfig
s390                             allyesconfig
s390                             allmodconfig
parisc                           allyesconfig
s390                                defconfig
i386                             allyesconfig
i386                               tinyconfig
i386                                defconfig
mips                             allyesconfig
mips                             allmodconfig
powerpc                          allyesconfig
powerpc                          allmodconfig
powerpc                           allnoconfig
i386                 randconfig-a001-20210311
i386                 randconfig-a005-20210311
i386                 randconfig-a003-20210311
i386                 randconfig-a002-20210311
i386                 randconfig-a004-20210311
i386                 randconfig-a006-20210311
x86_64               randconfig-a011-20210312
x86_64               randconfig-a016-20210312
x86_64               randconfig-a013-20210312
x86_64               randconfig-a014-20210312
x86_64               randconfig-a015-20210312
x86_64               randconfig-a012-20210312
i386                 randconfig-a013-20210311
i386                 randconfig-a016-20210311
i386                 randconfig-a011-20210311
i386                 randconfig-a014-20210311
i386                 randconfig-a015-20210311
i386                 randconfig-a012-20210311
i386                 randconfig-a013-20210312
i386                 randconfig-a016-20210312
i386                 randconfig-a011-20210312
i386                 randconfig-a015-20210312
i386                 randconfig-a014-20210312
i386                 randconfig-a012-20210312
x86_64               randconfig-a006-20210311
x86_64               randconfig-a001-20210311
x86_64               randconfig-a005-20210311
x86_64               randconfig-a002-20210311
x86_64               randconfig-a003-20210311
x86_64               randconfig-a004-20210311
riscv                    nommu_virt_defconfig
riscv                             allnoconfig
riscv                          rv32_defconfig
riscv                            allmodconfig
riscv                    nommu_k210_defconfig
riscv                            allyesconfig
x86_64                           allyesconfig
x86_64                    rhel-7.6-kselftests
x86_64                              defconfig
x86_64                               rhel-8.3
x86_64                      rhel-8.3-kbuiltin
x86_64                                  kexec

clang tested configs:
x86_64               randconfig-a006-20210312
x86_64               randconfig-a001-20210312
x86_64               randconfig-a005-20210312
x86_64               randconfig-a003-20210312
x86_64               randconfig-a002-20210312
x86_64               randconfig-a004-20210312
x86_64               randconfig-a011-20210311
x86_64               randconfig-a016-20210311
x86_64               randconfig-a013-20210311
x86_64               randconfig-a015-20210311
x86_64               randconfig-a014-20210311
x86_64               randconfig-a012-20210311

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

^ permalink raw reply

* [powerpc:fixes] BUILD SUCCESS 0b736881c8f1a6cd912f7a9162b9e097b28c1c30
From: kernel test robot @ 2021-03-12 12:38 UTC (permalink / raw)
  To: Michael Ellerman; +Cc: linuxppc-dev

tree/branch: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git fixes
branch HEAD: 0b736881c8f1a6cd912f7a9162b9e097b28c1c30  powerpc/traps: unrecoverable_exception() is not an interrupt handler

elapsed time: 732m

configs tested: 106
configs skipped: 20

The following configs have been built successfully.
More configs may be tested in the coming days.

gcc tested configs:
nds32                            alldefconfig
powerpc                    socrates_defconfig
sh                           se7712_defconfig
arm                          collie_defconfig
riscv                               defconfig
powerpc                    ge_imp3a_defconfig
sh                             sh03_defconfig
arm                             mxs_defconfig
sh                        dreamcast_defconfig
arm                          ixp4xx_defconfig
h8300                               defconfig
arc                          axs101_defconfig
sh                   sh7724_generic_defconfig
m68k                         apollo_defconfig
arm                         lpc32xx_defconfig
m68k                          multi_defconfig
powerpc                  mpc866_ads_defconfig
powerpc                      ep88xc_defconfig
sh                        sh7763rdp_defconfig
arm                        neponset_defconfig
sh                 kfr2r09-romimage_defconfig
ia64                          tiger_defconfig
arm                       netwinder_defconfig
arm                        magician_defconfig
mips                        bcm63xx_defconfig
powerpc                 mpc832x_rdb_defconfig
arm64                            alldefconfig
sh                          r7785rp_defconfig
arc                           tb10x_defconfig
arm                        keystone_defconfig
arm                        trizeps4_defconfig
sparc                               defconfig
parisc                generic-64bit_defconfig
mips                          malta_defconfig
m68k                        mvme147_defconfig
powerpc                      ppc40x_defconfig
powerpc                     tqm8548_defconfig
arm                         s3c6400_defconfig
mips                        nlm_xlr_defconfig
arm                          iop32x_defconfig
sparc                       sparc32_defconfig
sh                        edosk7705_defconfig
powerpc                 mpc836x_mds_defconfig
arm                                 defconfig
ia64                             allmodconfig
ia64                                defconfig
ia64                             allyesconfig
m68k                             allmodconfig
m68k                                defconfig
m68k                             allyesconfig
nios2                               defconfig
arc                              allyesconfig
nds32                             allnoconfig
nds32                               defconfig
nios2                            allyesconfig
csky                                defconfig
alpha                               defconfig
alpha                            allyesconfig
xtensa                           allyesconfig
h8300                            allyesconfig
arc                                 defconfig
sh                               allmodconfig
parisc                              defconfig
s390                             allyesconfig
s390                             allmodconfig
parisc                           allyesconfig
s390                                defconfig
i386                             allyesconfig
sparc                            allyesconfig
i386                               tinyconfig
i386                                defconfig
mips                             allyesconfig
mips                             allmodconfig
powerpc                          allyesconfig
powerpc                          allmodconfig
powerpc                           allnoconfig
i386                 randconfig-a001-20210311
i386                 randconfig-a005-20210311
i386                 randconfig-a003-20210311
i386                 randconfig-a002-20210311
i386                 randconfig-a004-20210311
i386                 randconfig-a006-20210311
i386                 randconfig-a013-20210311
i386                 randconfig-a016-20210311
i386                 randconfig-a011-20210311
i386                 randconfig-a014-20210311
i386                 randconfig-a015-20210311
i386                 randconfig-a012-20210311
x86_64               randconfig-a006-20210311
x86_64               randconfig-a001-20210311
x86_64               randconfig-a005-20210311
x86_64               randconfig-a002-20210311
x86_64               randconfig-a003-20210311
x86_64               randconfig-a004-20210311
x86_64                           allyesconfig
x86_64                    rhel-7.6-kselftests
x86_64                              defconfig
x86_64                               rhel-8.3
x86_64                      rhel-8.3-kbuiltin
x86_64                                  kexec

clang tested configs:
x86_64               randconfig-a011-20210311
x86_64               randconfig-a016-20210311
x86_64               randconfig-a013-20210311
x86_64               randconfig-a015-20210311
x86_64               randconfig-a014-20210311
x86_64               randconfig-a012-20210311

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

^ permalink raw reply

* [powerpc:fixes-test] BUILD SUCCESS cb6627c4919fb7023111d362391add9f848d2a91
From: kernel test robot @ 2021-03-12 12:38 UTC (permalink / raw)
  To: Michael Ellerman; +Cc: linuxppc-dev

tree/branch: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git fixes-test
branch HEAD: cb6627c4919fb7023111d362391add9f848d2a91  powerpc/eeh: Fix build failure with CONFIG_PROC_FS=n

elapsed time: 731m

configs tested: 106
configs skipped: 20

The following configs have been built successfully.
More configs may be tested in the coming days.

gcc tested configs:
nds32                            alldefconfig
powerpc                    socrates_defconfig
sh                           se7712_defconfig
arm                          collie_defconfig
riscv                               defconfig
powerpc                    ge_imp3a_defconfig
sh                             sh03_defconfig
arm                             mxs_defconfig
sh                        dreamcast_defconfig
arm                          ixp4xx_defconfig
h8300                               defconfig
arc                          axs101_defconfig
sh                   sh7724_generic_defconfig
m68k                         apollo_defconfig
arm                         lpc32xx_defconfig
m68k                          multi_defconfig
powerpc                  mpc866_ads_defconfig
powerpc                      ep88xc_defconfig
sh                        sh7763rdp_defconfig
arm                        neponset_defconfig
sh                 kfr2r09-romimage_defconfig
ia64                          tiger_defconfig
arm                       netwinder_defconfig
arm                        magician_defconfig
mips                        bcm63xx_defconfig
powerpc                 mpc832x_rdb_defconfig
arm64                            alldefconfig
sh                          r7785rp_defconfig
arc                           tb10x_defconfig
arm                        keystone_defconfig
arm                        trizeps4_defconfig
sparc                               defconfig
parisc                generic-64bit_defconfig
mips                          malta_defconfig
m68k                        mvme147_defconfig
powerpc                      ppc40x_defconfig
powerpc                     tqm8548_defconfig
arm                         s3c6400_defconfig
mips                        nlm_xlr_defconfig
arm                          iop32x_defconfig
sparc                       sparc32_defconfig
sh                        edosk7705_defconfig
powerpc                 mpc836x_mds_defconfig
arm                                 defconfig
ia64                             allmodconfig
ia64                                defconfig
ia64                             allyesconfig
m68k                             allmodconfig
m68k                                defconfig
m68k                             allyesconfig
nios2                               defconfig
arc                              allyesconfig
nds32                             allnoconfig
nds32                               defconfig
nios2                            allyesconfig
csky                                defconfig
alpha                               defconfig
alpha                            allyesconfig
xtensa                           allyesconfig
h8300                            allyesconfig
arc                                 defconfig
sh                               allmodconfig
parisc                              defconfig
s390                             allyesconfig
s390                             allmodconfig
parisc                           allyesconfig
s390                                defconfig
i386                             allyesconfig
sparc                            allyesconfig
i386                               tinyconfig
i386                                defconfig
mips                             allyesconfig
mips                             allmodconfig
powerpc                          allyesconfig
powerpc                          allmodconfig
powerpc                           allnoconfig
i386                 randconfig-a001-20210311
i386                 randconfig-a005-20210311
i386                 randconfig-a003-20210311
i386                 randconfig-a002-20210311
i386                 randconfig-a004-20210311
i386                 randconfig-a006-20210311
i386                 randconfig-a013-20210311
i386                 randconfig-a016-20210311
i386                 randconfig-a011-20210311
i386                 randconfig-a014-20210311
i386                 randconfig-a015-20210311
i386                 randconfig-a012-20210311
x86_64               randconfig-a006-20210311
x86_64               randconfig-a001-20210311
x86_64               randconfig-a005-20210311
x86_64               randconfig-a002-20210311
x86_64               randconfig-a003-20210311
x86_64               randconfig-a004-20210311
x86_64                           allyesconfig
x86_64                    rhel-7.6-kselftests
x86_64                              defconfig
x86_64                               rhel-8.3
x86_64                      rhel-8.3-kbuiltin
x86_64                                  kexec

clang tested configs:
x86_64               randconfig-a011-20210311
x86_64               randconfig-a016-20210311
x86_64               randconfig-a013-20210311
x86_64               randconfig-a015-20210311
x86_64               randconfig-a014-20210311
x86_64               randconfig-a012-20210311

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

^ permalink raw reply

* [powerpc:next-test] BUILD SUCCESS acc48fec3ae30fd2c049c39582e1c4fdf25480ee
From: kernel test robot @ 2021-03-12 12:38 UTC (permalink / raw)
  To: Michael Ellerman; +Cc: linuxppc-dev

tree/branch: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next-test
branch HEAD: acc48fec3ae30fd2c049c39582e1c4fdf25480ee  powerpc/uprobes: Validation for prefixed instruction

elapsed time: 727m

configs tested: 120
configs skipped: 2

The following configs have been built successfully.
More configs may be tested in the coming days.

gcc tested configs:
arm                                 defconfig
arm64                            allyesconfig
arm64                               defconfig
arm                              allyesconfig
arm                              allmodconfig
arm                             mxs_defconfig
sh                   secureedge5410_defconfig
ia64                          tiger_defconfig
arm                           spitz_defconfig
ia64                             alldefconfig
arm                         mv78xx0_defconfig
arm                          exynos_defconfig
m68k                        m5272c3_defconfig
arm                         nhk8815_defconfig
powerpc                      tqm8xx_defconfig
arm                     davinci_all_defconfig
powerpc                      pasemi_defconfig
powerpc                     powernv_defconfig
arm                   milbeaut_m10v_defconfig
arm                       versatile_defconfig
m68k                        m5307c3_defconfig
mips                      pistachio_defconfig
sh                 kfr2r09-romimage_defconfig
x86_64                           allyesconfig
arm                       netwinder_defconfig
arm                        magician_defconfig
mips                        bcm63xx_defconfig
powerpc                 mpc832x_rdb_defconfig
arm64                            alldefconfig
sh                          r7785rp_defconfig
arc                           tb10x_defconfig
arm                        keystone_defconfig
arm                        trizeps4_defconfig
mips                          malta_defconfig
mips                        nlm_xlr_defconfig
arm                  colibri_pxa270_defconfig
arm                        oxnas_v6_defconfig
powerpc                        icon_defconfig
arm                     eseries_pxa_defconfig
arm                         bcm2835_defconfig
arc                      axs103_smp_defconfig
mips                           ci20_defconfig
sh                           se7721_defconfig
powerpc                    ge_imp3a_defconfig
sh                          kfr2r09_defconfig
arm                        mvebu_v7_defconfig
mips                         tb0287_defconfig
nios2                         10m50_defconfig
arm                         palmz72_defconfig
alpha                               defconfig
sh                        sh7757lcr_defconfig
sh                          rsk7201_defconfig
ia64                             allmodconfig
ia64                                defconfig
ia64                             allyesconfig
m68k                             allmodconfig
m68k                                defconfig
m68k                             allyesconfig
nios2                               defconfig
arc                              allyesconfig
nds32                             allnoconfig
nds32                               defconfig
nios2                            allyesconfig
csky                                defconfig
alpha                            allyesconfig
xtensa                           allyesconfig
h8300                            allyesconfig
arc                                 defconfig
sh                               allmodconfig
parisc                              defconfig
s390                             allyesconfig
s390                             allmodconfig
parisc                           allyesconfig
s390                                defconfig
i386                             allyesconfig
sparc                            allyesconfig
sparc                               defconfig
i386                               tinyconfig
i386                                defconfig
mips                             allyesconfig
mips                             allmodconfig
powerpc                          allyesconfig
powerpc                          allmodconfig
powerpc                           allnoconfig
x86_64               randconfig-a006-20210311
x86_64               randconfig-a001-20210311
x86_64               randconfig-a005-20210311
x86_64               randconfig-a002-20210311
x86_64               randconfig-a003-20210311
x86_64               randconfig-a004-20210311
i386                 randconfig-a001-20210311
i386                 randconfig-a005-20210311
i386                 randconfig-a003-20210311
i386                 randconfig-a002-20210311
i386                 randconfig-a004-20210311
i386                 randconfig-a006-20210311
i386                 randconfig-a013-20210311
i386                 randconfig-a016-20210311
i386                 randconfig-a011-20210311
i386                 randconfig-a014-20210311
i386                 randconfig-a015-20210311
i386                 randconfig-a012-20210311
riscv                    nommu_k210_defconfig
riscv                            allyesconfig
riscv                    nommu_virt_defconfig
riscv                             allnoconfig
riscv                               defconfig
riscv                          rv32_defconfig
riscv                            allmodconfig
x86_64                    rhel-7.6-kselftests
x86_64                              defconfig
x86_64                               rhel-8.3
x86_64                      rhel-8.3-kbuiltin
x86_64                                  kexec

clang tested configs:
x86_64               randconfig-a006-20210312
x86_64               randconfig-a001-20210312
x86_64               randconfig-a005-20210312
x86_64               randconfig-a003-20210312
x86_64               randconfig-a002-20210312
x86_64               randconfig-a004-20210312

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

^ permalink raw reply

* [PATCH v3 04/41] powerpc/40x: Save SRR0/SRR1 and r10/r11 earlier in critical exception
From: Christophe Leroy @ 2021-03-12 12:50 UTC (permalink / raw)
  To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman, npiggin
  Cc: linuxppc-dev, linux-kernel
In-Reply-To: <cover.1615552866.git.christophe.leroy@csgroup.eu>

In order to be able to switch MMU on in exception prolog, save
SRR0 and SRR1 earlier.

Also save r10 and r11 into stack earlier to better match with the
normal exception prolog.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/kernel/entry_32.S | 9 ---------
 arch/powerpc/kernel/head_40x.S | 8 ++++++++
 2 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 78c430b7f9d9..8528b4c7f9d3 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -107,15 +107,6 @@ _ASM_NOKPROBE_SYMBOL(crit_transfer_to_handler)
 #ifdef CONFIG_40x
 	.globl	crit_transfer_to_handler
 crit_transfer_to_handler:
-	lwz	r0,crit_r10@l(0)
-	stw	r0,GPR10(r11)
-	lwz	r0,crit_r11@l(0)
-	stw	r0,GPR11(r11)
-	mfspr	r0,SPRN_SRR0
-	stw	r0,crit_srr0@l(0)
-	mfspr	r0,SPRN_SRR1
-	stw	r0,crit_srr1@l(0)
-
 	/* set the stack limit to the current stack */
 	mfspr	r8,SPRN_SPRG_THREAD
 	lwz	r0,KSP_LIMIT(r8)
diff --git a/arch/powerpc/kernel/head_40x.S b/arch/powerpc/kernel/head_40x.S
index 9cef423d574b..067ae1302c1c 100644
--- a/arch/powerpc/kernel/head_40x.S
+++ b/arch/powerpc/kernel/head_40x.S
@@ -103,6 +103,10 @@ _ENTRY(saved_ksp_limit)
 .macro CRITICAL_EXCEPTION_PROLOG
 	stw	r10,crit_r10@l(0)	/* save two registers to work with */
 	stw	r11,crit_r11@l(0)
+	mfspr	r10,SPRN_SRR0
+	mfspr	r11,SPRN_SRR1
+	stw	r10,crit_srr0@l(0)
+	stw	r11,crit_srr1@l(0)
 	mfcr	r10			/* save CR in r10 for now	   */
 	mfspr	r11,SPRN_SRR3		/* check whether user or kernel    */
 	andi.	r11,r11,MSR_PR
@@ -120,6 +124,10 @@ _ENTRY(saved_ksp_limit)
 	stw	r9,GPR9(r11)
 	mflr	r10
 	stw	r10,_LINK(r11)
+	lwz	r10,crit_r10@l(0)
+	lwz	r12,crit_r11@l(0)
+	stw	r10,GPR10(r11)
+	stw	r12,GPR11(r11)
 	mfspr	r12,SPRN_DEAR		/* save DEAR and ESR in the frame  */
 	stw	r12,_DEAR(r11)		/* since they may have had stuff   */
 	mfspr	r9,SPRN_ESR		/* in them at the point where the  */
-- 
2.25.0


^ permalink raw reply related

* [PATCH v3 02/41] powerpc/40x: Don't use SPRN_SPRG_SCRATCH0/1 in TLB miss handlers
From: Christophe Leroy @ 2021-03-12 12:50 UTC (permalink / raw)
  To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman, npiggin
  Cc: linuxppc-dev, linux-kernel
In-Reply-To: <cover.1615552866.git.christophe.leroy@csgroup.eu>

SPRN_SPRG_SCRATCH5 is used to save SPRN_PID.
SPRN_SPRG_SCRATCH6 is already available.

SPRN_PID is only 8 bits. We have r12 that contains CR.
We only need to preserve CR0, so we have space available in r12
to save PID.

Keep PID in r12 and free up SPRN_SPRG_SCRATCH5.

Then In TLB miss handlers, instead of using SPRN_SPRG_SCRATCH0 and
SPRN_SPRG_SCRATCH1, use SPRN_SPRG_SCRATCH5 and SPRN_SPRG_SCRATCH6
to avoid future conflicts with normal exception prologs.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/kernel/head_40x.S | 39 ++++++++++++++++------------------
 1 file changed, 18 insertions(+), 21 deletions(-)

diff --git a/arch/powerpc/kernel/head_40x.S b/arch/powerpc/kernel/head_40x.S
index 24724a7dad49..383238a98f77 100644
--- a/arch/powerpc/kernel/head_40x.S
+++ b/arch/powerpc/kernel/head_40x.S
@@ -249,13 +249,13 @@ _ENTRY(saved_ksp_limit)
  * load TLB entries from the page table if they exist.
  */
 	START_EXCEPTION(0x1100,	DTLBMiss)
-	mtspr	SPRN_SPRG_SCRATCH0, r10 /* Save some working registers */
-	mtspr	SPRN_SPRG_SCRATCH1, r11
+	mtspr	SPRN_SPRG_SCRATCH5, r10 /* Save some working registers */
+	mtspr	SPRN_SPRG_SCRATCH6, r11
 	mtspr	SPRN_SPRG_SCRATCH3, r12
 	mtspr	SPRN_SPRG_SCRATCH4, r9
 	mfcr	r12
 	mfspr	r9, SPRN_PID
-	mtspr	SPRN_SPRG_SCRATCH5, r9
+	rlwimi	r12, r9, 0, 0xff
 	mfspr	r10, SPRN_DEAR		/* Get faulting address */
 
 	/* If we are faulting a kernel address, we have to use the
@@ -316,13 +316,12 @@ _ENTRY(saved_ksp_limit)
 	/* The bailout.  Restore registers to pre-exception conditions
 	 * and call the heavyweights to help us out.
 	 */
-	mfspr	r9, SPRN_SPRG_SCRATCH5
-	mtspr	SPRN_PID, r9
-	mtcr	r12
+	mtspr	SPRN_PID, r12
+	mtcrf	0x80, r12
 	mfspr	r9, SPRN_SPRG_SCRATCH4
 	mfspr	r12, SPRN_SPRG_SCRATCH3
-	mfspr	r11, SPRN_SPRG_SCRATCH1
-	mfspr	r10, SPRN_SPRG_SCRATCH0
+	mfspr	r11, SPRN_SPRG_SCRATCH6
+	mfspr	r10, SPRN_SPRG_SCRATCH5
 	b	DataStorage
 
 /* 0x1200 - Instruction TLB Miss Exception
@@ -330,13 +329,13 @@ _ENTRY(saved_ksp_limit)
  * registers and bailout to a different point.
  */
 	START_EXCEPTION(0x1200,	ITLBMiss)
-	mtspr	SPRN_SPRG_SCRATCH0, r10	 /* Save some working registers */
-	mtspr	SPRN_SPRG_SCRATCH1, r11
+	mtspr	SPRN_SPRG_SCRATCH5, r10	 /* Save some working registers */
+	mtspr	SPRN_SPRG_SCRATCH6, r11
 	mtspr	SPRN_SPRG_SCRATCH3, r12
 	mtspr	SPRN_SPRG_SCRATCH4, r9
 	mfcr	r12
 	mfspr	r9, SPRN_PID
-	mtspr	SPRN_SPRG_SCRATCH5, r9
+	rlwimi	r12, r9, 0, 0xff
 	mfspr	r10, SPRN_SRR0		/* Get faulting address */
 
 	/* If we are faulting a kernel address, we have to use the
@@ -397,13 +396,12 @@ _ENTRY(saved_ksp_limit)
 	/* The bailout.  Restore registers to pre-exception conditions
 	 * and call the heavyweights to help us out.
 	 */
-	mfspr	r9, SPRN_SPRG_SCRATCH5
-	mtspr	SPRN_PID, r9
-	mtcr	r12
+	mtspr	SPRN_PID, r12
+	mtcrf	0x80, r12
 	mfspr	r9, SPRN_SPRG_SCRATCH4
 	mfspr	r12, SPRN_SPRG_SCRATCH3
-	mfspr	r11, SPRN_SPRG_SCRATCH1
-	mfspr	r10, SPRN_SPRG_SCRATCH0
+	mfspr	r11, SPRN_SPRG_SCRATCH6
+	mfspr	r10, SPRN_SPRG_SCRATCH5
 	b	InstructionAccess
 
 	EXCEPTION(0x1300, Trap_13, unknown_exception, EXC_XFER_STD)
@@ -543,13 +541,12 @@ finish_tlb_load:
 
 	/* Done...restore registers and get out of here.
 	*/
-	mfspr	r9, SPRN_SPRG_SCRATCH5
-	mtspr	SPRN_PID, r9
-	mtcr	r12
+	mtspr	SPRN_PID, r12
+	mtcrf	0x80, r12
 	mfspr	r9, SPRN_SPRG_SCRATCH4
 	mfspr	r12, SPRN_SPRG_SCRATCH3
-	mfspr	r11, SPRN_SPRG_SCRATCH1
-	mfspr	r10, SPRN_SPRG_SCRATCH0
+	mfspr	r11, SPRN_SPRG_SCRATCH6
+	mfspr	r10, SPRN_SPRG_SCRATCH5
 	rfi			/* Should sync shadow TLBs */
 	b	.		/* prevent prefetch past rfi */
 
-- 
2.25.0


^ permalink raw reply related

* [PATCH v3 03/41] powerpc/40x: Change CRITICAL_EXCEPTION_PROLOG macro to a gas macro
From: Christophe Leroy @ 2021-03-12 12:50 UTC (permalink / raw)
  To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman, npiggin
  Cc: linuxppc-dev, linux-kernel
In-Reply-To: <cover.1615552866.git.christophe.leroy@csgroup.eu>

Change CRITICAL_EXCEPTION_PROLOG macro to a gas macro to
remove the ugly ; and \ on each line.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/kernel/head_40x.S | 71 +++++++++++++++++-----------------
 1 file changed, 36 insertions(+), 35 deletions(-)

diff --git a/arch/powerpc/kernel/head_40x.S b/arch/powerpc/kernel/head_40x.S
index 383238a98f77..9cef423d574b 100644
--- a/arch/powerpc/kernel/head_40x.S
+++ b/arch/powerpc/kernel/head_40x.S
@@ -100,42 +100,43 @@ _ENTRY(saved_ksp_limit)
  * Instead we use a couple of words of memory at low physical addresses.
  * This is OK since we don't support SMP on these processors.
  */
-#define CRITICAL_EXCEPTION_PROLOG					     \
-	stw	r10,crit_r10@l(0);	/* save two registers to work with */\
-	stw	r11,crit_r11@l(0);					     \
-	mfcr	r10;			/* save CR in r10 for now	   */\
-	mfspr	r11,SPRN_SRR3;		/* check whether user or kernel    */\
-	andi.	r11,r11,MSR_PR;						     \
-	lis	r11,critirq_ctx@ha;					     \
-	tophys(r11,r11);						     \
-	lwz	r11,critirq_ctx@l(r11);					     \
-	beq	1f;							     \
-	/* COMING FROM USER MODE */					     \
-	mfspr	r11,SPRN_SPRG_THREAD;	/* if from user, start at top of   */\
-	lwz	r11,TASK_STACK-THREAD(r11); /* this thread's kernel stack */\
-1:	addi	r11,r11,THREAD_SIZE-INT_FRAME_SIZE; /* Alloc an excpt frm  */\
-	tophys(r11,r11);						     \
-	stw	r10,_CCR(r11);          /* save various registers	   */\
-	stw	r12,GPR12(r11);						     \
-	stw	r9,GPR9(r11);						     \
-	mflr	r10;							     \
-	stw	r10,_LINK(r11);						     \
-	mfspr	r12,SPRN_DEAR;		/* save DEAR and ESR in the frame  */\
-	stw	r12,_DEAR(r11);		/* since they may have had stuff   */\
-	mfspr	r9,SPRN_ESR;		/* in them at the point where the  */\
-	stw	r9,_ESR(r11);		/* exception was taken		   */\
-	mfspr	r12,SPRN_SRR2;						     \
-	stw	r1,GPR1(r11);						     \
-	mfspr	r9,SPRN_SRR3;						     \
-	stw	r1,0(r11);						     \
-	tovirt(r1,r11);							     \
-	rlwinm	r9,r9,0,14,12;		/* clear MSR_WE (necessary?)	   */\
-	stw	r0,GPR0(r11);						     \
-	lis	r10, STACK_FRAME_REGS_MARKER@ha; /* exception frame marker */\
-	addi	r10, r10, STACK_FRAME_REGS_MARKER@l;			     \
-	stw	r10, 8(r11);						     \
-	SAVE_4GPRS(3, r11);						     \
+.macro CRITICAL_EXCEPTION_PROLOG
+	stw	r10,crit_r10@l(0)	/* save two registers to work with */
+	stw	r11,crit_r11@l(0)
+	mfcr	r10			/* save CR in r10 for now	   */
+	mfspr	r11,SPRN_SRR3		/* check whether user or kernel    */
+	andi.	r11,r11,MSR_PR
+	lis	r11,critirq_ctx@ha
+	tophys(r11,r11)
+	lwz	r11,critirq_ctx@l(r11)
+	beq	1f
+	/* COMING FROM USER MODE */
+	mfspr	r11,SPRN_SPRG_THREAD	/* if from user, start at top of   */
+	lwz	r11,TASK_STACK-THREAD(r11) /* this thread's kernel stack */
+1:	addi	r11,r11,THREAD_SIZE-INT_FRAME_SIZE /* Alloc an excpt frm  */
+	tophys(r11,r11)
+	stw	r10,_CCR(r11)		/* save various registers	   */
+	stw	r12,GPR12(r11)
+	stw	r9,GPR9(r11)
+	mflr	r10
+	stw	r10,_LINK(r11)
+	mfspr	r12,SPRN_DEAR		/* save DEAR and ESR in the frame  */
+	stw	r12,_DEAR(r11)		/* since they may have had stuff   */
+	mfspr	r9,SPRN_ESR		/* in them at the point where the  */
+	stw	r9,_ESR(r11)		/* exception was taken		   */
+	mfspr	r12,SPRN_SRR2
+	stw	r1,GPR1(r11)
+	mfspr	r9,SPRN_SRR3
+	stw	r1,0(r11)
+	tovirt(r1,r11)
+	rlwinm	r9,r9,0,14,12		/* clear MSR_WE (necessary?)	   */
+	stw	r0,GPR0(r11)
+	lis	r10, STACK_FRAME_REGS_MARKER@ha /* exception frame marker */
+	addi	r10, r10, STACK_FRAME_REGS_MARKER@l
+	stw	r10, 8(r11)
+	SAVE_4GPRS(3, r11)
 	SAVE_2GPRS(7, r11)
+.endm
 
 	/*
 	 * State at this point:
-- 
2.25.0


^ permalink raw reply related

* [PATCH v3 00/41] powerpc/32: Switch to interrupt entry/exit in C
From: Christophe Leroy @ 2021-03-12 12:50 UTC (permalink / raw)
  To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman, npiggin
  Cc: linuxppc-dev, linux-kernel

This series aims at porting interrupt entry/exit in C on PPC32, using
the work already merged for PPC64.

First patch is an optimisation around unrecoverable_exception() function.

Six following patches do minimal changes in 40x in order to be able to enable MMU
earlier in exception entry.

Second part of the series prepares and switches interrupt exit in C.

Third part moves more and more things in C, ending with KUAP management.

v3 is tested on 8xx and 83xx and qemu mac99 and qemu bamboo.

Changes in v3:
- Remove the WARN in first patch
- Fix oopses due fast_interrupt_return clobering registers after FPunavailable expection.
- Only call restore_math if PPC64
- Rename C version of kuap_{get_and_}check() into kuap_{get_and_}assert_locked().
- Drop the patch to call bad_page_fault() from do_page_fault() on book3e/64
- Remove the unneeded setting of current->thread.regs on every interrupt entry from user.

Changes in v2:
- Two first patches are new.
- Mainly build fixes, nothing much new.

Christophe Leroy (41):
  powerpc/traps: Declare unrecoverable_exception() as __noreturn
  powerpc/40x: Don't use SPRN_SPRG_SCRATCH0/1 in TLB miss handlers
  powerpc/40x: Change CRITICAL_EXCEPTION_PROLOG macro to a gas macro
  powerpc/40x: Save SRR0/SRR1 and r10/r11 earlier in critical exception
  powerpc/40x: Reorder a few instructions in critical exception prolog
  powerpc/40x: Prepare for enabling MMU in critical exception prolog
  powerpc/40x: Prepare normal exception handler for enabling MMU early
  powerpc/32: Reconcile interrupts in C
  powerpc/32: Entry cpu time accounting in C
  powerpc/32: Handle bookE debugging in C in exception entry
  powerpc/32: Use fast instruction to set MSR RI in exception prolog on
    8xx
  powerpc/32: Remove ksp_limit
  powerpc/32: Always enable data translation in exception prolog
  powerpc/32: Tag DAR in EXCEPTION_PROLOG_2 for the 8xx
  powerpc/32: Enable instruction translation at the same time as data
    translation
  powerpc/32: Statically initialise first emergency context
  powerpc/32: Add vmap_stack_overflow label inside the macro
  powerpc/32: Use START_EXCEPTION() as much as possible
  powerpc/32: Move exception prolog code into .text once MMU is back on
  powerpc/32: Provide a name to exception prolog continuation in virtual
    mode
  powerpc/32: Refactor booke critical registers saving
  powerpc/32: Perform normal function call in exception entry
  powerpc/32: Always save non volatile registers on exception entry
  powerpc/32: Replace ASM exception exit by C exception exit from ppc64
  powerpc/32: Don't save thread.regs on interrupt entry
  powerpc/32: Set regs parameter in r3 in transfer_to_handler
  powerpc/32: Call bad_page_fault() from do_page_fault()
  powerpc/32: Save trap number on stack in exception prolog
  powerpc/32: Add a prepare_transfer_to_handler macro for exception
    prologs
  powerpc/32: Only restore non volatile registers when required
  powerpc/32: Dismantle EXC_XFER_STD/LITE/TEMPLATE
  powerpc/32: Remove the xfer parameter in EXCEPTION() macro
  powerpc/32: Refactor saving of volatile registers in exception prologs
  powerpc/32: Save remaining registers in exception prolog
  powerpc/32: Return directly from power_save_ppc32_restore()
  powerpc/32: Only use prepare_transfer_to_handler function on book3s/32
    and e500
  powerpc/32s: Move KUEP locking/unlocking in C
  powerpc/64s: Make kuap_check_amr() and kuap_get_and_check_amr()
    generic
  powerpc/32s: Create C version of kuap save/restore/check helpers
  powerpc/8xx: Create C version of kuap save/restore/check helpers
  powerpc/32: Manage KUAP in C

 arch/powerpc/include/asm/book3s/32/kup.h     | 126 ++-
 arch/powerpc/include/asm/book3s/64/kup.h     |  24 +-
 arch/powerpc/include/asm/interrupt.h         |  17 +-
 arch/powerpc/include/asm/kup.h               |  27 +-
 arch/powerpc/include/asm/nohash/32/kup-8xx.h |  56 +-
 arch/powerpc/include/asm/ppc_asm.h           |  10 -
 arch/powerpc/include/asm/processor.h         |   6 +-
 arch/powerpc/include/asm/ptrace.h            |   6 +-
 arch/powerpc/kernel/asm-offsets.c            |   4 -
 arch/powerpc/kernel/entry_32.S               | 796 ++++---------------
 arch/powerpc/kernel/fpu.S                    |   2 -
 arch/powerpc/kernel/head_32.h                | 198 ++---
 arch/powerpc/kernel/head_40x.S               | 271 ++++---
 arch/powerpc/kernel/head_44x.S               |  10 +-
 arch/powerpc/kernel/head_8xx.S               | 151 ++--
 arch/powerpc/kernel/head_book3s_32.S         | 233 +++---
 arch/powerpc/kernel/head_booke.h             | 203 +++--
 arch/powerpc/kernel/head_fsl_booke.S         |  64 +-
 arch/powerpc/kernel/idle_6xx.S               |  14 +-
 arch/powerpc/kernel/idle_e500.S              |  14 +-
 arch/powerpc/kernel/interrupt.c              |  41 +-
 arch/powerpc/kernel/irq.c                    |   2 +-
 arch/powerpc/kernel/misc_32.S                |  14 -
 arch/powerpc/kernel/process.c                |   6 +-
 arch/powerpc/kernel/setup_32.c               |   2 +-
 arch/powerpc/kernel/traps.c                  |  14 +-
 arch/powerpc/kernel/vector.S                 |   2 -
 arch/powerpc/lib/sstep.c                     |   9 -
 arch/powerpc/mm/book3s32/Makefile            |   1 +
 arch/powerpc/mm/book3s32/hash_low.S          |  14 -
 arch/powerpc/mm/book3s32/kuep.c              |  38 +
 arch/powerpc/mm/fault.c                      |   2 +-
 32 files changed, 887 insertions(+), 1490 deletions(-)
 create mode 100644 arch/powerpc/mm/book3s32/kuep.c

-- 
2.25.0


^ permalink raw reply


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