Re: [PATCH 2/3] powperc/mm: read TLB Block Invalidate Characteristics
From: Laurent Dufour
Date: Thu Sep 12 2019 - 15:27:23 EST
Le 12/09/2019 Ã 16:44, Aneesh Kumar K.V a ÃcritÂ:
Laurent Dufour <ldufour@xxxxxxxxxxxxx> writes:
The PAPR document specifies the TLB Block Invalidate Characteristics which
is telling which couple base page size / page size is supported by the
H_BLOCK_REMOVE hcall.
A new set of feature is added to the mmu_psize_def structure to record per
base page size which page size is supported by H_BLOCK_REMOVE.
A new init service is added to read the characteristics. The size of the
buffer is set to twice the number of known page size, plus 10 bytes to
ensure we have enough place.
Signed-off-by: Laurent Dufour <ldufour@xxxxxxxxxxxxx>
---
arch/powerpc/include/asm/book3s/64/mmu.h | 3 +
arch/powerpc/platforms/pseries/lpar.c | 107 +++++++++++++++++++++++
2 files changed, 110 insertions(+)
diff --git a/arch/powerpc/include/asm/book3s/64/mmu.h b/arch/powerpc/include/asm/book3s/64/mmu.h
index 23b83d3593e2..675895dfe39f 100644
--- a/arch/powerpc/include/asm/book3s/64/mmu.h
+++ b/arch/powerpc/include/asm/book3s/64/mmu.h
@@ -12,11 +12,14 @@
* sllp : is a bit mask with the value of SLB L || LP to be or'ed
* directly to a slbmte "vsid" value
* penc : is the HPTE encoding mask for the "LP" field:
+ * hblk : H_BLOCK_REMOVE supported block size for this page size in
+ * segment who's base page size is that page size.
*
*/
struct mmu_psize_def {
unsigned int shift; /* number of bits */
int penc[MMU_PAGE_COUNT]; /* HPTE encoding */
+ int hblk[MMU_PAGE_COUNT]; /* H_BLOCK_REMOVE support */
unsigned int tlbiel; /* tlbiel supported for that page size */
unsigned long avpnm; /* bits to mask out in AVPN in the HPTE */
union {
diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
index 4f76e5f30c97..375e19b3cf53 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -1311,6 +1311,113 @@ static void do_block_remove(unsigned long number, struct ppc64_tlb_batch *batch,
(void)call_block_remove(pix, param, true);
}
+static inline void __init set_hblk_bloc_size(int bpsize, int psize,
+ unsigned int block_size)
+{
+ struct mmu_psize_def *def = &mmu_psize_defs[bpsize];
+
+ if (block_size > def->hblk[psize])
+ def->hblk[psize] = block_size;
+}
+
+static inline void __init check_lp_set_hblk(unsigned int lp,
+ unsigned int block_size)
+{
+ unsigned int bpsize, psize;
+
+
+ /* First, check the L bit, if not set, this means 4K */
+ if ((lp & 0x80) == 0) {
+ set_hblk_bloc_size(MMU_PAGE_4K, MMU_PAGE_4K, block_size);
+ return;
+ }
+
+ /* PAPR says to look at bits 2-7 (0 = MSB) */
+ lp &= 0x3f;
+ for (bpsize = 0; bpsize < MMU_PAGE_COUNT; bpsize++) {
+ struct mmu_psize_def *def = &mmu_psize_defs[bpsize];
+
+ for (psize = 0; psize < MMU_PAGE_COUNT; psize++) {
+ if (def->penc[psize] == lp) {
+ set_hblk_bloc_size(bpsize, psize, block_size);
+ return;
+ }
+ }
+ }
+}
+
+#define SPLPAR_TLB_BIC_TOKEN 50
+#define SPLPAR_TLB_BIC_MAXLENGTH (MMU_PAGE_COUNT*2 + 10)
+static int __init read_tlbbi_characteristics(void)
+{
+ int call_status;
+ unsigned char local_buffer[SPLPAR_TLB_BIC_MAXLENGTH];
+ int len, idx, bpsize;
+
+ if (!firmware_has_feature(FW_FEATURE_BLOCK_REMOVE)) {
+ pr_info("H_BLOCK_REMOVE is not supported");
+ return 0;
+ }
+
+ memset(local_buffer, 0, SPLPAR_TLB_BIC_MAXLENGTH);
+
+ spin_lock(&rtas_data_buf_lock);
+ memset(rtas_data_buf, 0, RTAS_DATA_BUF_SIZE);
+ call_status = rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1,
+ NULL,
+ SPLPAR_TLB_BIC_TOKEN,
+ __pa(rtas_data_buf),
+ RTAS_DATA_BUF_SIZE);
+ memcpy(local_buffer, rtas_data_buf, SPLPAR_TLB_BIC_MAXLENGTH);
+ local_buffer[SPLPAR_TLB_BIC_MAXLENGTH - 1] = '\0';
+ spin_unlock(&rtas_data_buf_lock);
+
+ if (call_status != 0) {
+ pr_warn("%s %s Error calling get-system-parameter (0x%x)\n",
+ __FILE__, __func__, call_status);
+ return 0;
+ }
+
+ /*
+ * The first two (2) bytes of the data in the buffer are the length of
+ * the returned data, not counting these first two (2) bytes.
+ */
+ len = local_buffer[0] * 256 + local_buffer[1] + 2;
+ if (len >= SPLPAR_TLB_BIC_MAXLENGTH) {
+ pr_warn("%s too large returned buffer %d", __func__, len);
+ return 0;
+ }
+
+ idx = 2;
+ while (idx < len) {
+ unsigned int block_size = local_buffer[idx++];
+ unsigned int npsize;
+
+ if (!block_size)
+ break;
+
+ block_size = 1 << block_size;
+ if (block_size != 8)
+ /* We only support 8 bytes size TLB invalidate buffer */
+ pr_warn("Unsupported H_BLOCK_REMOVE block size : %d\n",
+ block_size);
Should we skip setting block size if we find block_size != 8? Also can
we avoid doing that pr_warn in loop and only warn if we don't find
block_size 8 in the invalidate characteristics array?
My idea here is to fully read and process the data returned by the hcall,
and to put the limitation to 8 when checking before calling H_BLOCK_REMOVE.
The warning is there because I want it to be displayed once at boot.
+
+ for (npsize = local_buffer[idx++]; npsize > 0; npsize--)
+ check_lp_set_hblk((unsigned int) local_buffer[idx++],
+ block_size);
+ }
+
+ for (bpsize = 0; bpsize < MMU_PAGE_COUNT; bpsize++)
+ for (idx = 0; idx < MMU_PAGE_COUNT; idx++)
+ if (mmu_psize_defs[bpsize].hblk[idx])
+ pr_info("H_BLOCK_REMOVE supports base psize:%d psize:%d block size:%d",
+ bpsize, idx,
+ mmu_psize_defs[bpsize].hblk[idx]);
+
+ return 0;
+}
+machine_arch_initcall(pseries, read_tlbbi_characteristics);
+
/*
* Take a spinlock around flushes to avoid bouncing the hypervisor tlbie
* lock.
--
2.23.0