[PATCH v3 4/6] s390/boot: Add dfltcc= kernel command line parameter

Mikhail Zaslonko
2020-01-03T22:33:56Z

Add the new kernel command line parameter 'dfltcc=' to configure
s390 zlib hardware support.
Format: { on | off | def_only | inf_only | always }
on: s390 zlib hardware support for compression on
level 1 and decompression (default)
off: No s390 zlib hardware support
def_only: s390 zlib hardware support for deflate
only (compression on level 1)
inf_only: s390 zlib hardware support for inflate
only (decompression)
always: Same as 'on' but ignores the selected compression
level always using hardware support (used for debugging)

Signed-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
---
Documentation/admin-guide/kernel-parameters.txt | 12 ++++++++++++
arch/s390/boot/ipl_parm.c | 14 ++++++++++++++
arch/s390/include/asm/setup.h | 7 +++++++
arch/s390/kernel/setup.c | 2 ++
lib/zlib_dfltcc/dfltcc.c | 5 ++++-
lib/zlib_dfltcc/dfltcc.h | 1 +
lib/zlib_dfltcc/dfltcc_deflate.c | 6 ++++++
lib/zlib_dfltcc/dfltcc_inflate.c | 6 ++++++
lib/zlib_dfltcc/dfltcc_util.h | 4 +++-
9 files changed, 55 insertions(+), 2 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index ade4e6ec23e0..08fcbaa69877 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -834,6 +834,18 @@
dump out devices still on the deferred probe list after
retrying.

+ dfltcc= [HW,S390]
+ Format: { on | off | def_only | inf_only | always }
+ on: s390 zlib hardware support for compression on
+ level 1 and decompression (default)
+ off: No s390 zlib hardware support
+ def_only: s390 zlib hardware support for deflate
+ only (compression on level 1)
+ inf_only: s390 zlib hardware support for inflate
+ only (decompression)
+ always: Same as 'on' but ignores the selected compression
+ level always using hardware support (used for debugging)
+
dhash_entries= [KNL]
Set number of hash buckets for dentry cache.

diff --git a/arch/s390/boot/ipl_parm.c b/arch/s390/boot/ipl_parm.c
index 24ef67eb1cef..357adad991d2 100644
--- a/arch/s390/boot/ipl_parm.c
+++ b/arch/s390/boot/ipl_parm.c
@@ -14,6 +14,7 @@
char __bootdata(early_command_line)[COMMAND_LINE_SIZE];
struct ipl_parameter_block __bootdata_preserved(ipl_block);
int __bootdata_preserved(ipl_block_valid);
+unsigned int __bootdata_preserved(zlib_dfltcc_support) = ZLIB_DFLTCC_FULL;

unsigned long __bootdata(vmalloc_size) = VMALLOC_DEFAULT_SIZE;
unsigned long __bootdata(memory_end);
@@ -229,6 +230,19 @@ void parse_boot_command_line(void)
if (!strcmp(param, "vmalloc") && val)
vmalloc_size = round_up(memparse(val, NULL), PAGE_SIZE);

+ if (!strcmp(param, "dfltcc")) {
+ if (!strcmp(val, "off"))
+ zlib_dfltcc_support = ZLIB_DFLTCC_DISABLED;
+ else if (!strcmp(val, "on"))
+ zlib_dfltcc_support = ZLIB_DFLTCC_FULL;
+ else if (!strcmp(val, "def_only"))
+ zlib_dfltcc_support = ZLIB_DFLTCC_DEFLATE_ONLY;
+ else if (!strcmp(val, "inf_only"))
+ zlib_dfltcc_support = ZLIB_DFLTCC_INFLATE_ONLY;
+ else if (!strcmp(val, "always"))
+ zlib_dfltcc_support = ZLIB_DFLTCC_FULL_DEBUG;
+ }
+
if (!strcmp(param, "noexec")) {
rc = kstrtobool(val, &enabled);
if (!rc && !enabled)
diff --git a/arch/s390/include/asm/setup.h b/arch/s390/include/asm/setup.h
index 69289e99cabd..b241ddb67caf 100644
--- a/arch/s390/include/asm/setup.h
+++ b/arch/s390/include/asm/setup.h
@@ -79,6 +79,13 @@ struct parmarea {
char command_line[ARCH_COMMAND_LINE_SIZE]; /* 0x10480 */
};

+extern unsigned int zlib_dfltcc_support;
+#define ZLIB_DFLTCC_DISABLED 0
+#define ZLIB_DFLTCC_FULL 1
+#define ZLIB_DFLTCC_DEFLATE_ONLY 2
+#define ZLIB_DFLTCC_INFLATE_ONLY 3
+#define ZLIB_DFLTCC_FULL_DEBUG 4
+
extern int noexec_disabled;
extern int memory_end_set;
extern unsigned long memory_end;
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 9cbf490fd162..a577d7df379c 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -111,6 +111,8 @@ unsigned long __bootdata_preserved(__etext_dma);
unsigned long __bootdata_preserved(__sdma);
unsigned long __bootdata_preserved(__edma);
unsigned long __bootdata_preserved(__kaslr_offset);
+unsigned int __bootdata_preserved(zlib_dfltcc_support);
+EXPORT_SYMBOL(zlib_dfltcc_support);

unsigned long VMALLOC_START;
EXPORT_SYMBOL(VMALLOC_START);
diff --git a/lib/zlib_dfltcc/dfltcc.c b/lib/zlib_dfltcc/dfltcc.c
index 7f77e5bb01c6..c30de430b30c 100644
--- a/lib/zlib_dfltcc/dfltcc.c
+++ b/lib/zlib_dfltcc/dfltcc.c
@@ -44,7 +44,10 @@ void dfltcc_reset(
dfltcc_state->param.nt = 1;

/* Initialize tuning parameters */
- dfltcc_state->level_mask = DFLTCC_LEVEL_MASK;
+ if (zlib_dfltcc_support == ZLIB_DFLTCC_FULL_DEBUG)
+ dfltcc_state->level_mask = DFLTCC_LEVEL_MASK_DEBUG;
+ else
+ dfltcc_state->level_mask = DFLTCC_LEVEL_MASK;
dfltcc_state->block_size = DFLTCC_BLOCK_SIZE;
dfltcc_state->block_threshold = DFLTCC_FIRST_FHT_BLOCK_SIZE;
dfltcc_state->dht_threshold = DFLTCC_DHT_MIN_SAMPLE_SIZE;
diff --git a/lib/zlib_dfltcc/dfltcc.h b/lib/zlib_dfltcc/dfltcc.h
index 4782c92bb2ff..be70c807b62f 100644
--- a/lib/zlib_dfltcc/dfltcc.h
+++ b/lib/zlib_dfltcc/dfltcc.h
@@ -8,6 +8,7 @@
* Tuning parameters.
*/
#define DFLTCC_LEVEL_MASK 0x2 /* DFLTCC compression for level 1 only */
+#define DFLTCC_LEVEL_MASK_DEBUG 0x3fe /* DFLTCC compression for all levels */
#define DFLTCC_BLOCK_SIZE 1048576
#define DFLTCC_FIRST_FHT_BLOCK_SIZE 4096
#define DFLTCC_DHT_MIN_SAMPLE_SIZE 4096
diff --git a/lib/zlib_dfltcc/dfltcc_deflate.c b/lib/zlib_dfltcc/dfltcc_deflate.c
index b9d16917c30a..aa4539f5c071 100644
--- a/lib/zlib_dfltcc/dfltcc_deflate.c
+++ b/lib/zlib_dfltcc/dfltcc_deflate.c
@@ -3,6 +3,7 @@
#include "../zlib_deflate/defutil.h"
#include "dfltcc_util.h"
#include "dfltcc.h"
+#include <asm/setup.h>
#include <linux/zutil.h>

/*
@@ -15,6 +16,11 @@ int dfltcc_can_deflate(
deflate_state *state = (deflate_state *)strm->state;
struct dfltcc_state *dfltcc_state = GET_DFLTCC_STATE(state);

+ /* Check for kernel dfltcc command line parameter */
+ if (zlib_dfltcc_support == ZLIB_DFLTCC_DISABLED ||
+ zlib_dfltcc_support == ZLIB_DFLTCC_INFLATE_ONLY)
+ return 0;
+
/* Unsupported compression settings */
if (!dfltcc_are_params_ok(state->level, state->w_bits, state->strategy,
dfltcc_state->level_mask))
diff --git a/lib/zlib_dfltcc/dfltcc_inflate.c b/lib/zlib_dfltcc/dfltcc_inflate.c
index 12a93a06bd61..aa9ef23474df 100644
--- a/lib/zlib_dfltcc/dfltcc_inflate.c
+++ b/lib/zlib_dfltcc/dfltcc_inflate.c
@@ -3,6 +3,7 @@
#include "../zlib_inflate/inflate.h"
#include "dfltcc_util.h"
#include "dfltcc.h"
+#include <asm/setup.h>
#include <linux/zutil.h>

/*
@@ -15,6 +16,11 @@ int dfltcc_can_inflate(
struct inflate_state *state = (struct inflate_state *)strm->state;
struct dfltcc_state *dfltcc_state = GET_DFLTCC_STATE(state);

+ /* Check for kernel dfltcc command line parameter */
+ if (zlib_dfltcc_support == ZLIB_DFLTCC_DISABLED ||
+ zlib_dfltcc_support == ZLIB_DFLTCC_DEFLATE_ONLY)
+ return 0;
+
/* Unsupported compression settings */
if (state->wbits != HB_BITS)
return 0;
diff --git a/lib/zlib_dfltcc/dfltcc_util.h b/lib/zlib_dfltcc/dfltcc_util.h
index 82cd1950c416..7c0d3bdc50a9 100644
--- a/lib/zlib_dfltcc/dfltcc_util.h
+++ b/lib/zlib_dfltcc/dfltcc_util.h
@@ -4,6 +4,7 @@

#include <linux/zutil.h>
#include <asm/facility.h>
+#include <asm/setup.h>

/*
* C wrapper for the DEFLATE CONVERSION CALL instruction.
@@ -102,7 +103,8 @@ static inline int dfltcc_are_params_ok(

static inline int is_dfltcc_enabled(void)
{
- return test_facility(DFLTCC_FACILITY);
+ return (zlib_dfltcc_support != ZLIB_DFLTCC_DISABLED &&
+ test_facility(DFLTCC_FACILITY));
}

char *oesc_msg(char *buf, int oesc);
--
2.17.1