s390/boot: add dfltcc= kernel command line parameter

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)

Link: http:https://lkml.kernel.org/r/[email protected]
Signed-off-by: Mikhail Zaslonko <[email protected]>
Cc: Chris Mason <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: David Sterba <[email protected]>
Cc: Eduard Shishkin <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Ilya Leoshkevich <[email protected]>
Cc: Josef Bacik <[email protected]>
Cc: Richard Purdie <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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.
 

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)

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;

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);

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;

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

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))

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;

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);