From 1211ee61b4a8e60d6dc77211cdcf01906915bfba Mon Sep 17 00:00:00 2001
From: Laurent Dufour <ldufour@linux.ibm.com>
Date: Fri, 20 Sep 2019 15:05:22 +0200
Subject: [PATCH] powerpc/pseries: Read TLB Block Invalidate Characteristics
References: bsc#1109158
Patch-mainline: v5.4-rc1
Git-commit: 1211ee61b4a8e60d6dc77211cdcf01906915bfba
The PAPR document specifies the TLB Block Invalidate Characteristics
which tells for each pair of segment base page size, actual page size,
the size of the block the hcall H_BLOCK_REMOVE supports.
These characteristics are loaded at boot time in a new table
hblkr_size. The table is separate from the mmu_psize_def because this
is specific to the pseries platform.
A new init function, pseries_lpar_read_hblkrm_characteristics() is
added to read the characteristics. It is called from
pSeries_setup_arch().
Fixes: ba2dd8a26baa ("powerpc/pseries/mm: call H_BLOCK_REMOVE")
Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190920130523.20441-2-ldufour@linux.ibm.com
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
arch/powerpc/platforms/pseries/lpar.c | 140 +++++++++++++++++++++++
arch/powerpc/platforms/pseries/pseries.h | 1 +
arch/powerpc/platforms/pseries/setup.c | 1 +
3 files changed, 142 insertions(+)
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -64,6 +64,15 @@ EXPORT_SYMBOL(plpar_hcall);
EXPORT_SYMBOL(plpar_hcall9);
EXPORT_SYMBOL(plpar_hcall_norets);
+/*
+ * H_BLOCK_REMOVE supported block size for this page size in segment who's base
+ * page size is that page size.
+ *
+ * The first index is the segment base page size, the second one is the actual
+ * page size.
+ */
+static int hblkrm_size[MMU_PAGE_COUNT][MMU_PAGE_COUNT] __ro_after_init;
+
void vpa_init(int cpu)
{
int hwcpu = get_hard_smp_processor_id(cpu);
@@ -753,6 +762,137 @@ static void do_block_remove(unsigned lon
}
/*
+ * TLB Block Invalidate Characteristics
+ *
+ * These characteristics define the size of the block the hcall H_BLOCK_REMOVE
+ * is able to process for each couple segment base page size, actual page size.
+ *
+ * The ibm,get-system-parameter properties is returning a buffer with the
+ * following layout:
+ *
+ * [ 2 bytes size of the RTAS buffer (excluding these 2 bytes) ]
+ * -----------------
+ * TLB Block Invalidate Specifiers:
+ * [ 1 byte LOG base 2 of the TLB invalidate block size being specified ]
+ * [ 1 byte Number of page sizes (N) that are supported for the specified
+ * TLB invalidate block size ]
+ * [ 1 byte Encoded segment base page size and actual page size
+ * MSB=0 means 4k segment base page size and actual page size
+ * MSB=1 the penc value in mmu_psize_def ]
+ * ...
+ * -----------------
+ * Next TLB Block Invalidate Specifiers...
+ * -----------------
+ * [ 0 ]
+ */
+static inline void set_hblkrm_bloc_size(int bpsize, int psize,
+ unsigned int block_size)
+{
+ if (block_size > hblkrm_size[bpsize][psize])
+ hblkrm_size[bpsize][psize] = block_size;
+}
+
+/*
+ * Decode the Encoded segment base page size and actual page size.
+ * PAPR specifies:
+ * - bit 7 is the L bit
+ * - bits 0-5 are the penc value
+ * If the L bit is 0, this means 4K segment base page size and actual page size
+ * otherwise the penc value should be read.
+ */
+#define HBLKRM_L_MASK 0x80
+#define HBLKRM_PENC_MASK 0x3f
+static inline void __init check_lp_set_hblkrm(unsigned int lp,
+ unsigned int block_size)
+{
+ unsigned int bpsize, psize;
+
+ /* First, check the L bit, if not set, this means 4K */
+ if ((lp & HBLKRM_L_MASK) == 0) {
+ set_hblkrm_bloc_size(MMU_PAGE_4K, MMU_PAGE_4K, block_size);
+ return;
+ }
+
+ lp &= HBLKRM_PENC_MASK;
+ 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_hblkrm_bloc_size(bpsize, psize, block_size);
+ return;
+ }
+ }
+ }
+}
+
+#define SPLPAR_TLB_BIC_TOKEN 50
+
+/*
+ * The size of the TLB Block Invalidate Characteristics is variable. But at the
+ * maximum it will be the number of possible page sizes *2 + 10 bytes.
+ * Currently MMU_PAGE_COUNT is 16, which means 42 bytes. Use a cache line size
+ * (128 bytes) for the buffer to get plenty of space.
+ */
+#define SPLPAR_TLB_BIC_MAXLENGTH 128
+
+void __init pseries_lpar_read_hblkrm_characteristics(void)
+{
+ unsigned char local_buffer[SPLPAR_TLB_BIC_MAXLENGTH];
+ int call_status, len, idx, bpsize;
+
+ 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;
+ }
+
+ /*
+ * 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 = be16_to_cpu(*((u16 *)local_buffer)) + 2;
+ if (len > SPLPAR_TLB_BIC_MAXLENGTH) {
+ pr_warn("%s too large returned buffer %d", __func__, len);
+ return;
+ }
+
+ idx = 2;
+ while (idx < len) {
+ u8 block_shift = local_buffer[idx++];
+ u32 block_size;
+ unsigned int npsize;
+
+ if (!block_shift)
+ break;
+
+ block_size = 1 << block_shift;
+
+ for (npsize = local_buffer[idx++];
+ npsize > 0 && idx < len; npsize--)
+ check_lp_set_hblkrm((unsigned int) local_buffer[idx++],
+ block_size);
+ }
+
+ for (bpsize = 0; bpsize < MMU_PAGE_COUNT; bpsize++)
+ for (idx = 0; idx < MMU_PAGE_COUNT; idx++)
+ if (hblkrm_size[bpsize][idx])
+ pr_info("H_BLOCK_REMOVE supports base psize:%d psize:%d block size:%d",
+ bpsize, idx, hblkrm_size[bpsize][idx]);
+}
+
+/*
* Take a spinlock around flushes to avoid bouncing the hypervisor tlbie
* lock.
*/
--- a/arch/powerpc/platforms/pseries/pseries.h
+++ b/arch/powerpc/platforms/pseries/pseries.h
@@ -103,5 +103,6 @@ static inline unsigned long cmo_get_page
int dlpar_workqueue_init(void);
void pseries_setup_rfi_flush(void);
+void pseries_lpar_read_hblkrm_characteristics(void);
#endif /* _PSERIES_PSERIES_H */
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -759,6 +759,7 @@ static void __init pSeries_setup_arch(vo
pseries_setup_rfi_flush();
setup_stf_barrier();
+ pseries_lpar_read_hblkrm_characteristics();
/* By default, only probe PCI (can be overridden by rtas_pci) */
pci_add_flags(PCI_PROBE_ONLY);