* [kvm-unit-tests PATCH v2 0/2] s390x: Avoid gcc 12 warnings
@ 2022-05-20 14:05 Janis Schoetterl-Glausch
2022-05-20 14:05 ` [kvm-unit-tests PATCH v2 1/2] s390x: Introduce symbol for lowcore and use it Janis Schoetterl-Glausch
` (2 more replies)
0 siblings, 3 replies; 8+ messages in thread
From: Janis Schoetterl-Glausch @ 2022-05-20 14:05 UTC (permalink / raw)
To: Thomas Huth, Janosch Frank, Claudio Imbrenda
Cc: Janis Schoetterl-Glausch, David Hildenbrand, kvm, linux-s390
gcc 12 warns if a memory operand to inline asm points to memory in the
first 4k bytes. However, in our case, these operands are fine, either
because we actually want to use that memory, or expect and handle the
resulting exception.
v1 -> v2
* replace mechanism, don't use pragmas, instead use an extern symbol so
gcc cannot conclude that the pointer is <4k
This new extern symbol refers to the lowcore. As a result, code
generation for lowcore accesses becomes worse.
Alternatives:
* Don't use extern symbol for lowcore, just for problematic pointers
* Hide value from gcc via inline asm
* Disable the warning globally
* Use memory clobber instead of memory output
Use address in register input instead of memory input
(may require WRITE_ONCE)
* Don't use gcc 12.0, with newer versions --param=min-pagesize=0 might
avoid the problem
Janis Schoetterl-Glausch (2):
s390x: Introduce symbol for lowcore and use it
s390x: Fix gcc 12 warning about array bounds
lib/s390x/asm/arch_def.h | 2 ++
lib/s390x/asm/facility.h | 4 +--
lib/s390x/asm/mem.h | 4 +++
lib/s390x/css.h | 2 --
lib/s390x/css_lib.c | 12 ++++----
lib/s390x/fault.c | 10 +++----
lib/s390x/interrupt.c | 61 +++++++++++++++++++-------------------
lib/s390x/mmu.c | 3 +-
s390x/flat.lds | 1 +
s390x/snippets/c/flat.lds | 1 +
s390x/css.c | 4 +--
s390x/diag288.c | 4 +--
s390x/edat.c | 5 ++--
s390x/emulator.c | 15 +++++-----
s390x/mvpg.c | 7 ++---
s390x/sclp.c | 3 +-
s390x/skey.c | 2 +-
s390x/skrf.c | 11 +++----
s390x/smp.c | 23 +++++++-------
s390x/snippets/c/spec_ex.c | 5 ++--
20 files changed, 83 insertions(+), 96 deletions(-)
base-commit: 8719e8326101c1be8256617caf5835b57e819339
--
2.33.1
^ permalink raw reply [flat|nested] 8+ messages in thread
* [kvm-unit-tests PATCH v2 1/2] s390x: Introduce symbol for lowcore and use it
2022-05-20 14:05 [kvm-unit-tests PATCH v2 0/2] s390x: Avoid gcc 12 warnings Janis Schoetterl-Glausch
@ 2022-05-20 14:05 ` Janis Schoetterl-Glausch
2022-05-24 7:42 ` Claudio Imbrenda
2022-06-03 13:12 ` Thomas Huth
2022-05-20 14:05 ` [kvm-unit-tests PATCH v2 2/2] s390x: Fix gcc 12 warning about array bounds Janis Schoetterl-Glausch
2022-05-24 7:39 ` [kvm-unit-tests PATCH v2 0/2] s390x: Avoid gcc 12 warnings Claudio Imbrenda
2 siblings, 2 replies; 8+ messages in thread
From: Janis Schoetterl-Glausch @ 2022-05-20 14:05 UTC (permalink / raw)
To: Thomas Huth, Janosch Frank, Claudio Imbrenda
Cc: Janis Schoetterl-Glausch, David Hildenbrand, kvm, linux-s390
This gets rid of bunch of pointers pointing to the lowcore used in
various places and replaces it with a unified way of addressing the
lowcore.
The new symbol is not a pointer. While this will lead to worse code
generation (cannot use register 0 for addressing), that should not
matter too much for kvm unit tests.
The symbol also will be used to create pointers that the compiler cannot
warn about as being outside the bounds of an array.
Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
---
lib/s390x/asm/arch_def.h | 2 ++
lib/s390x/asm/facility.h | 4 +--
lib/s390x/css.h | 2 --
lib/s390x/css_lib.c | 12 ++++----
lib/s390x/fault.c | 10 +++----
lib/s390x/interrupt.c | 61 +++++++++++++++++++-------------------
lib/s390x/mmu.c | 3 +-
s390x/flat.lds | 1 +
s390x/snippets/c/flat.lds | 1 +
s390x/css.c | 4 +--
s390x/diag288.c | 4 +--
s390x/edat.c | 5 ++--
s390x/emulator.c | 10 +++----
s390x/mvpg.c | 7 ++---
s390x/sclp.c | 3 +-
s390x/skrf.c | 11 +++----
s390x/smp.c | 23 +++++++-------
s390x/snippets/c/spec_ex.c | 5 ++--
18 files changed, 75 insertions(+), 93 deletions(-)
diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
index 72553819..78b257b7 100644
--- a/lib/s390x/asm/arch_def.h
+++ b/lib/s390x/asm/arch_def.h
@@ -145,6 +145,8 @@ struct lowcore {
} __attribute__ ((__packed__));
_Static_assert(sizeof(struct lowcore) == 0x1900, "Lowcore size");
+extern struct lowcore lowcore;
+
#define PGM_INT_CODE_OPERATION 0x01
#define PGM_INT_CODE_PRIVILEGED_OPERATION 0x02
#define PGM_INT_CODE_EXECUTE 0x03
diff --git a/lib/s390x/asm/facility.h b/lib/s390x/asm/facility.h
index ef0fd037..49380203 100644
--- a/lib/s390x/asm/facility.h
+++ b/lib/s390x/asm/facility.h
@@ -36,10 +36,8 @@ static inline void stfle(uint64_t *fac, unsigned int nb_doublewords)
static inline void setup_facilities(void)
{
- struct lowcore *lc = NULL;
-
stfl();
- memcpy(stfl_doublewords, &lc->stfl, sizeof(lc->stfl));
+ memcpy(stfl_doublewords, &lowcore.stfl, sizeof(lowcore.stfl));
if (test_facility(7))
stfle(stfl_doublewords, NB_STFL_DOUBLEWORDS);
}
diff --git a/lib/s390x/css.h b/lib/s390x/css.h
index a6a68577..0a19324b 100644
--- a/lib/s390x/css.h
+++ b/lib/s390x/css.h
@@ -9,8 +9,6 @@
#ifndef _S390X_CSS_H_
#define _S390X_CSS_H_
-#define lowcore_ptr ((struct lowcore *)0x0)
-
/* subchannel ID bit 16 must always be one */
#define SCHID_ONE 0x00010000
diff --git a/lib/s390x/css_lib.c b/lib/s390x/css_lib.c
index a9f5097f..b4d1f086 100644
--- a/lib/s390x/css_lib.c
+++ b/lib/s390x/css_lib.c
@@ -357,11 +357,11 @@ void css_irq_io(void)
int sid;
report_prefix_push("Interrupt");
- sid = lowcore_ptr->subsys_id_word;
+ sid = lowcore.subsys_id_word;
/* Lowlevel set the SID as interrupt parameter. */
- if (lowcore_ptr->io_int_param != sid) {
+ if (lowcore.io_int_param != sid) {
report_fail("io_int_param: %x differs from subsys_id_word: %x",
- lowcore_ptr->io_int_param, sid);
+ lowcore.io_int_param, sid);
goto pop;
}
report_prefix_pop();
@@ -387,7 +387,7 @@ void css_irq_io(void)
}
pop:
report_prefix_pop();
- lowcore_ptr->io_old_psw.mask &= ~PSW_MASK_WAIT;
+ lowcore.io_old_psw.mask &= ~PSW_MASK_WAIT;
}
int start_ccw1_chain(unsigned int sid, struct ccw1 *ccw)
@@ -432,9 +432,9 @@ int wait_and_check_io_completion(int schid)
report_prefix_push("check I/O completion");
- if (lowcore_ptr->io_int_param != schid) {
+ if (lowcore.io_int_param != schid) {
report_fail("interrupt parameter: expected %08x got %08x",
- schid, lowcore_ptr->io_int_param);
+ schid, lowcore.io_int_param);
ret = -1;
goto end;
}
diff --git a/lib/s390x/fault.c b/lib/s390x/fault.c
index d3ef00e4..efa62fcb 100644
--- a/lib/s390x/fault.c
+++ b/lib/s390x/fault.c
@@ -13,8 +13,6 @@
#include <asm/page.h>
#include <fault.h>
-static struct lowcore *lc = (struct lowcore *)0x0;
-
/* Decodes the protection exceptions we'll most likely see */
static void print_decode_pgm_prot(uint64_t teid)
{
@@ -37,7 +35,7 @@ static void print_decode_pgm_prot(uint64_t teid)
void print_decode_teid(uint64_t teid)
{
int asce_id = teid & 3;
- bool dat = lc->pgm_old_psw.mask & PSW_MASK_DAT;
+ bool dat = lowcore.pgm_old_psw.mask & PSW_MASK_DAT;
printf("Memory exception information:\n");
printf("DAT: %s\n", dat ? "on" : "off");
@@ -58,15 +56,15 @@ void print_decode_teid(uint64_t teid)
break;
}
- if (lc->pgm_int_code == PGM_INT_CODE_PROTECTION)
+ if (lowcore.pgm_int_code == PGM_INT_CODE_PROTECTION)
print_decode_pgm_prot(teid);
/*
* If teid bit 61 is off for these two exception the reported
* address is unpredictable.
*/
- if ((lc->pgm_int_code == PGM_INT_CODE_SECURE_STOR_ACCESS ||
- lc->pgm_int_code == PGM_INT_CODE_SECURE_STOR_VIOLATION) &&
+ if ((lowcore.pgm_int_code == PGM_INT_CODE_SECURE_STOR_ACCESS ||
+ lowcore.pgm_int_code == PGM_INT_CODE_SECURE_STOR_VIOLATION) &&
!test_bit_inv(61, &teid)) {
printf("Address: %lx, unpredictable\n ", teid & PAGE_MASK);
return;
diff --git a/lib/s390x/interrupt.c b/lib/s390x/interrupt.c
index 27d3b767..6da20c44 100644
--- a/lib/s390x/interrupt.c
+++ b/lib/s390x/interrupt.c
@@ -18,20 +18,19 @@
static bool pgm_int_expected;
static bool ext_int_expected;
static void (*pgm_cleanup_func)(void);
-static struct lowcore *lc;
void expect_pgm_int(void)
{
pgm_int_expected = true;
- lc->pgm_int_code = 0;
- lc->trans_exc_id = 0;
+ lowcore.pgm_int_code = 0;
+ lowcore.trans_exc_id = 0;
mb();
}
void expect_ext_int(void)
{
ext_int_expected = true;
- lc->ext_int_code = 0;
+ lowcore.ext_int_code = 0;
mb();
}
@@ -40,9 +39,9 @@ uint16_t clear_pgm_int(void)
uint16_t code;
mb();
- code = lc->pgm_int_code;
- lc->pgm_int_code = 0;
- lc->trans_exc_id = 0;
+ code = lowcore.pgm_int_code;
+ lowcore.pgm_int_code = 0;
+ lowcore.trans_exc_id = 0;
pgm_int_expected = false;
return code;
}
@@ -50,9 +49,9 @@ uint16_t clear_pgm_int(void)
void check_pgm_int_code(uint16_t code)
{
mb();
- report(code == lc->pgm_int_code,
+ report(code == lowcore.pgm_int_code,
"Program interrupt: expected(%d) == received(%d)", code,
- lc->pgm_int_code);
+ lowcore.pgm_int_code);
}
void register_pgm_cleanup_func(void (*f)(void))
@@ -63,29 +62,29 @@ void register_pgm_cleanup_func(void (*f)(void))
static void fixup_pgm_int(struct stack_frame_int *stack)
{
/* If we have an error on SIE we directly move to sie_exit */
- if (lc->pgm_old_psw.addr >= (uint64_t)&sie_entry &&
- lc->pgm_old_psw.addr <= (uint64_t)&sie_exit) {
- lc->pgm_old_psw.addr = (uint64_t)&sie_exit;
+ if (lowcore.pgm_old_psw.addr >= (uint64_t)&sie_entry &&
+ lowcore.pgm_old_psw.addr <= (uint64_t)&sie_exit) {
+ lowcore.pgm_old_psw.addr = (uint64_t)&sie_exit;
}
- switch (lc->pgm_int_code) {
+ switch (lowcore.pgm_int_code) {
case PGM_INT_CODE_PRIVILEGED_OPERATION:
/* Normal operation is in supervisor state, so this exception
* was produced intentionally and we should return to the
* supervisor state.
*/
- lc->pgm_old_psw.mask &= ~PSW_MASK_PSTATE;
+ lowcore.pgm_old_psw.mask &= ~PSW_MASK_PSTATE;
break;
case PGM_INT_CODE_PROTECTION:
/* Handling for iep.c test case. */
- if (prot_is_iep(lc->trans_exc_id))
+ if (prot_is_iep(lowcore.trans_exc_id))
/*
* We branched to the instruction that caused
* the exception so we can use the return
* address in GR14 to jump back and continue
* executing test code.
*/
- lc->pgm_old_psw.addr = stack->grs0[12];
+ lowcore.pgm_old_psw.addr = stack->grs0[12];
break;
case PGM_INT_CODE_SEGMENT_TRANSLATION:
case PGM_INT_CODE_PAGE_TRANSLATION:
@@ -122,14 +121,14 @@ static void fixup_pgm_int(struct stack_frame_int *stack)
/* The interrupt was nullified, the old PSW points at the
* responsible instruction. Forward the PSW so we don't loop.
*/
- lc->pgm_old_psw.addr += lc->pgm_int_id;
+ lowcore.pgm_old_psw.addr += lowcore.pgm_int_id;
}
/* suppressed/terminated/completed point already at the next address */
}
static void print_storage_exception_information(void)
{
- switch (lc->pgm_int_code) {
+ switch (lowcore.pgm_int_code) {
case PGM_INT_CODE_PROTECTION:
case PGM_INT_CODE_PAGE_TRANSLATION:
case PGM_INT_CODE_SEGMENT_TRANSLATION:
@@ -140,7 +139,7 @@ static void print_storage_exception_information(void)
case PGM_INT_CODE_SECURE_STOR_ACCESS:
case PGM_INT_CODE_NON_SECURE_STOR_ACCESS:
case PGM_INT_CODE_SECURE_STOR_VIOLATION:
- print_decode_teid(lc->trans_exc_id);
+ print_decode_teid(lowcore.trans_exc_id);
break;
}
}
@@ -165,13 +164,13 @@ static void print_pgm_info(struct stack_frame_int *stack)
{
bool in_sie;
- in_sie = (lc->pgm_old_psw.addr >= (uintptr_t)sie_entry &&
- lc->pgm_old_psw.addr <= (uintptr_t)sie_exit);
+ in_sie = (lowcore.pgm_old_psw.addr >= (uintptr_t)sie_entry &&
+ lowcore.pgm_old_psw.addr <= (uintptr_t)sie_exit);
printf("\n");
printf("Unexpected program interrupt %s: %#x on cpu %d at %#lx, ilen %d\n",
in_sie ? "in SIE" : "",
- lc->pgm_int_code, stap(), lc->pgm_old_psw.addr, lc->pgm_int_id);
+ lowcore.pgm_int_code, stap(), lowcore.pgm_old_psw.addr, lowcore.pgm_int_id);
print_int_regs(stack);
dump_stack();
@@ -201,13 +200,13 @@ void handle_pgm_int(struct stack_frame_int *stack)
void handle_ext_int(struct stack_frame_int *stack)
{
if (!ext_int_expected &&
- lc->ext_int_code != EXT_IRQ_SERVICE_SIG) {
+ lowcore.ext_int_code != EXT_IRQ_SERVICE_SIG) {
report_abort("Unexpected external call interrupt (code %#x): on cpu %d at %#lx",
- lc->ext_int_code, stap(), lc->ext_old_psw.addr);
+ lowcore.ext_int_code, stap(), lowcore.ext_old_psw.addr);
return;
}
- if (lc->ext_int_code == EXT_IRQ_SERVICE_SIG) {
+ if (lowcore.ext_int_code == EXT_IRQ_SERVICE_SIG) {
stack->crs[0] &= ~(1UL << 9);
sclp_handle_ext();
} else {
@@ -215,13 +214,13 @@ void handle_ext_int(struct stack_frame_int *stack)
}
if (!(stack->crs[0] & CR0_EXTM_MASK))
- lc->ext_old_psw.mask &= ~PSW_MASK_EXT;
+ lowcore.ext_old_psw.mask &= ~PSW_MASK_EXT;
}
void handle_mcck_int(void)
{
report_abort("Unexpected machine check interrupt: on cpu %d at %#lx",
- stap(), lc->mcck_old_psw.addr);
+ stap(), lowcore.mcck_old_psw.addr);
}
static void (*io_int_func)(void);
@@ -232,7 +231,7 @@ void handle_io_int(void)
return io_int_func();
report_abort("Unexpected io interrupt: on cpu %d at %#lx",
- stap(), lc->io_old_psw.addr);
+ stap(), lowcore.io_old_psw.addr);
}
int register_io_int_func(void (*f)(void))
@@ -253,14 +252,14 @@ int unregister_io_int_func(void (*f)(void))
void handle_svc_int(void)
{
- uint16_t code = lc->svc_int_code;
+ uint16_t code = lowcore.svc_int_code;
switch (code) {
case SVC_LEAVE_PSTATE:
- lc->svc_old_psw.mask &= ~PSW_MASK_PSTATE;
+ lowcore.svc_old_psw.mask &= ~PSW_MASK_PSTATE;
break;
default:
report_abort("Unexpected supervisor call interrupt: code %#x on cpu %d at %#lx",
- code, stap(), lc->svc_old_psw.addr);
+ code, stap(), lowcore.svc_old_psw.addr);
}
}
diff --git a/lib/s390x/mmu.c b/lib/s390x/mmu.c
index 6f9e6502..c9f8754c 100644
--- a/lib/s390x/mmu.c
+++ b/lib/s390x/mmu.c
@@ -43,7 +43,6 @@ void configure_dat(int enable)
static void mmu_enable(pgd_t *pgtable)
{
- struct lowcore *lc = NULL;
const uint64_t asce = __pa(pgtable) | ASCE_DT_REGION1 |
REGION_TABLE_LENGTH;
@@ -55,7 +54,7 @@ static void mmu_enable(pgd_t *pgtable)
configure_dat(1);
/* we can now also use DAT unconditionally in our PGM handler */
- lc->pgm_new_psw.mask |= PSW_MASK_DAT;
+ lowcore.pgm_new_psw.mask |= PSW_MASK_DAT;
}
/*
diff --git a/s390x/flat.lds b/s390x/flat.lds
index 86dffacd..de9da1a8 100644
--- a/s390x/flat.lds
+++ b/s390x/flat.lds
@@ -7,6 +7,7 @@ SECTIONS
* address 0x10000 (cstart64.S .init).
*/
. = 0;
+ lowcore = .;
LONG(0x00080000)
LONG(0x80010000)
/* Restart new PSW for booting via PSW restart. */
diff --git a/s390x/snippets/c/flat.lds b/s390x/snippets/c/flat.lds
index 59974b38..260ab1c4 100644
--- a/s390x/snippets/c/flat.lds
+++ b/s390x/snippets/c/flat.lds
@@ -7,6 +7,7 @@ SECTIONS
* address 0x4000 (cstart.S .init).
*/
. = 0;
+ lowcore = .;
LONG(0x00080000)
LONG(0x80004000)
/* Restart new PSW for booting via PSW restart. */
diff --git a/s390x/css.c b/s390x/css.c
index fabe5237..4b6e31b3 100644
--- a/s390x/css.c
+++ b/s390x/css.c
@@ -74,7 +74,7 @@ static void test_sense(void)
return;
}
- lowcore_ptr->io_int_param = 0;
+ lowcore.io_int_param = 0;
senseid = alloc_io_mem(sizeof(*senseid), 0);
if (!senseid) {
@@ -143,7 +143,7 @@ static void sense_id(void)
static void css_init(void)
{
assert(register_io_int_func(css_irq_io) == 0);
- lowcore_ptr->io_int_param = 0;
+ lowcore.io_int_param = 0;
report(get_chsc_scsc(), "Store Channel Characteristics");
}
diff --git a/s390x/diag288.c b/s390x/diag288.c
index 072c04a5..e414865b 100644
--- a/s390x/diag288.c
+++ b/s390x/diag288.c
@@ -12,8 +12,6 @@
#include <asm/asm-offsets.h>
#include <asm/interrupt.h>
-struct lowcore *lc = (struct lowcore *)0x0;
-
#define CODE_INIT 0
#define CODE_CHANGE 1
#define CODE_CANCEL 2
@@ -92,7 +90,7 @@ static void test_bite(void)
load_psw_mask(mask);
/* Arm watchdog */
- lc->restart_new_psw.mask = extract_psw_mask() & ~PSW_MASK_EXT;
+ lowcore.restart_new_psw.mask = extract_psw_mask() & ~PSW_MASK_EXT;
diag288(CODE_INIT, 15, ACTION_RESTART);
asm volatile(" larl %r0, 1f\n"
" stg %r0, 424\n"
diff --git a/s390x/edat.c b/s390x/edat.c
index c3bee0c8..c6c25042 100644
--- a/s390x/edat.c
+++ b/s390x/edat.c
@@ -23,7 +23,6 @@
static uint8_t prefix_buf[LC_SIZE] __attribute__((aligned(LC_SIZE)));
static unsigned int tmp[1024] __attribute__((aligned(PAGE_SIZE)));
static void *root, *mem, *m;
-static struct lowcore *lc;
volatile unsigned int *p;
/*
@@ -34,10 +33,10 @@ static bool check_pgm_prot(void *ptr)
{
union teid teid;
- if (lc->pgm_int_code != PGM_INT_CODE_PROTECTION)
+ if (lowcore.pgm_int_code != PGM_INT_CODE_PROTECTION)
return false;
- teid.val = lc->trans_exc_id;
+ teid.val = lowcore.trans_exc_id;
/*
* depending on the presence of the ESOP feature, the rest of the
diff --git a/s390x/emulator.c b/s390x/emulator.c
index b2787a55..c9182ea4 100644
--- a/s390x/emulator.c
+++ b/s390x/emulator.c
@@ -14,8 +14,6 @@
#include <asm/float.h>
#include <linux/compiler.h>
-struct lowcore *lc = NULL;
-
static inline void __test_spm_ipm(uint8_t cc, uint8_t key)
{
uint64_t in = (cc << 28) | (key << 24);
@@ -262,7 +260,7 @@ static void test_prno(void)
static void test_dxc(void)
{
/* DXC (0xff) is to be stored in LC and FPC on a trap (CRT) with AFP */
- lc->dxc_vxc = 0x12345678;
+ lowcore.dxc_vxc = 0x12345678;
set_fpc_dxc(0);
report_prefix_push("afp");
@@ -271,12 +269,12 @@ static void test_dxc(void)
: : "r"(0) : "memory");
check_pgm_int_code(PGM_INT_CODE_DATA);
- report(lc->dxc_vxc == 0xff, "dxc in LC");
+ report(lowcore.dxc_vxc == 0xff, "dxc in LC");
report(get_fpc_dxc() == 0xff, "dxc in FPC");
report_prefix_pop();
/* DXC (0xff) is to be stored in LC only on a trap (CRT) without AFP */
- lc->dxc_vxc = 0x12345678;
+ lowcore.dxc_vxc = 0x12345678;
set_fpc_dxc(0);
report_prefix_push("no-afp");
@@ -288,7 +286,7 @@ static void test_dxc(void)
afp_enable();
check_pgm_int_code(PGM_INT_CODE_DATA);
- report(lc->dxc_vxc == 0xff, "dxc in LC");
+ report(lowcore.dxc_vxc == 0xff, "dxc in LC");
report(get_fpc_dxc() == 0, "dxc not in FPC");
report_prefix_pop();
}
diff --git a/s390x/mvpg.c b/s390x/mvpg.c
index 04e5218f..296338d4 100644
--- a/s390x/mvpg.c
+++ b/s390x/mvpg.c
@@ -33,7 +33,6 @@
static uint8_t source[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
static uint8_t buffer[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
-static struct lowcore * const lc;
/* Keep track of fresh memory */
static uint8_t *fresh;
@@ -87,7 +86,7 @@ static int page_ok(const uint8_t *p)
*/
static inline bool check_oai(void)
{
- return *(uint8_t *)(lc->pgm_old_psw.addr - 1) == lc->op_acc_id;
+ return *(uint8_t *)(lowcore.pgm_old_psw.addr - 1) == lowcore.op_acc_id;
}
static void test_exceptions(void)
@@ -216,7 +215,7 @@ static void test_mmu_prot(void)
report_prefix_push("source invalid");
protect_page(source, PAGE_ENTRY_I);
- lc->op_acc_id = 0;
+ lowcore.op_acc_id = 0;
expect_pgm_int();
mvpg(0, fresh, source);
report(clear_pgm_int() == PGM_INT_CODE_PAGE_TRANSLATION, "exception");
@@ -227,7 +226,7 @@ static void test_mmu_prot(void)
report_prefix_push("destination invalid");
protect_page(fresh, PAGE_ENTRY_I);
- lc->op_acc_id = 0;
+ lowcore.op_acc_id = 0;
expect_pgm_int();
mvpg(0, fresh, source);
report(clear_pgm_int() == PGM_INT_CODE_PAGE_TRANSLATION, "exception");
diff --git a/s390x/sclp.c b/s390x/sclp.c
index 73d722fb..1abb9029 100644
--- a/s390x/sclp.c
+++ b/s390x/sclp.c
@@ -31,7 +31,6 @@ static union {
WriteEventData data;
} sccb_template;
static uint32_t valid_code; /* valid command code for READ SCP INFO */
-static struct lowcore *lc;
/**
* Perform one service call, handling exceptions and interrupts.
@@ -43,7 +42,7 @@ static int sclp_service_call_test(unsigned int command, void *sccb)
sclp_mark_busy();
sclp_setup_int();
cc = servc(command, __pa(sccb));
- if (lc->pgm_int_code) {
+ if (lowcore.pgm_int_code) {
sclp_handle_ext();
return 0;
}
diff --git a/s390x/skrf.c b/s390x/skrf.c
index b9a2e902..1a811894 100644
--- a/s390x/skrf.c
+++ b/s390x/skrf.c
@@ -123,17 +123,15 @@ static void set_flag(int val)
static void ecall_cleanup(void)
{
- struct lowcore *lc = (void *)0x0;
-
- lc->ext_new_psw.mask = PSW_MASK_64;
- lc->sw_int_crs[0] = BIT_ULL(CTL0_AFP);
+ lowcore.ext_new_psw.mask = PSW_MASK_64;
+ lowcore.sw_int_crs[0] = BIT_ULL(CTL0_AFP);
/*
* PGM old contains the ext new PSW, we need to clean it up,
* so we don't get a special operation exception on the lpswe
* of pgm old.
*/
- lc->pgm_old_psw.mask = PSW_MASK_64;
+ lowcore.pgm_old_psw.mask = PSW_MASK_64;
check_pgm_int_code(PGM_INT_CODE_SPECIFICATION);
set_flag(1);
@@ -142,13 +140,12 @@ static void ecall_cleanup(void)
/* Set a key into the external new psw mask and open external call masks */
static void ecall_setup(void)
{
- struct lowcore *lc = (void *)0x0;
uint64_t mask;
register_pgm_cleanup_func(ecall_cleanup);
expect_pgm_int();
/* Put a skey into the ext new psw */
- lc->ext_new_psw.mask = 0x00F0000000000000UL | PSW_MASK_64;
+ lowcore.ext_new_psw.mask = 0x00F0000000000000UL | PSW_MASK_64;
/* Open up ext masks */
ctl_set_bit(0, CTL0_EXTERNAL_CALL);
mask = extract_psw_mask();
diff --git a/s390x/smp.c b/s390x/smp.c
index de3aba71..6d474d0d 100644
--- a/s390x/smp.c
+++ b/s390x/smp.c
@@ -155,28 +155,27 @@ static void test_stop(void)
static void test_stop_store_status(void)
{
struct cpu *cpu = smp_cpu_from_idx(1);
- struct lowcore *lc = (void *)0x0;
report_prefix_push("stop store status");
report_prefix_push("running");
smp_cpu_restart(1);
- lc->prefix_sa = 0;
- lc->grs_sa[15] = 0;
+ lowcore.prefix_sa = 0;
+ lowcore.grs_sa[15] = 0;
smp_cpu_stop_store_status(1);
mb();
report(smp_cpu_stopped(1), "cpu stopped");
- report(lc->prefix_sa == (uint32_t)(uintptr_t)cpu->lowcore, "prefix");
- report(lc->grs_sa[15], "stack");
+ report(lowcore.prefix_sa == (uint32_t)(uintptr_t)cpu->lowcore, "prefix");
+ report(lowcore.grs_sa[15], "stack");
report_prefix_pop();
report_prefix_push("stopped");
- lc->prefix_sa = 0;
- lc->grs_sa[15] = 0;
+ lowcore.prefix_sa = 0;
+ lowcore.grs_sa[15] = 0;
smp_cpu_stop_store_status(1);
mb();
report(smp_cpu_stopped(1), "cpu stopped");
- report(lc->prefix_sa == (uint32_t)(uintptr_t)cpu->lowcore, "prefix");
- report(lc->grs_sa[15], "stack");
+ report(lowcore.prefix_sa == (uint32_t)(uintptr_t)cpu->lowcore, "prefix");
+ report(lowcore.grs_sa[15], "stack");
report_prefix_pop();
report_prefix_pop();
@@ -290,7 +289,6 @@ static void test_set_prefix(void)
static void ecall(void)
{
unsigned long mask;
- struct lowcore *lc = (void *)0x0;
expect_ext_int();
ctl_set_bit(0, CTL0_EXTERNAL_CALL);
@@ -298,7 +296,7 @@ static void ecall(void)
mask |= PSW_MASK_EXT;
load_psw_mask(mask);
set_flag(1);
- while (lc->ext_int_code != 0x1202) { mb(); }
+ while (lowcore.ext_int_code != 0x1202) { mb(); }
report_pass("received");
set_flag(1);
}
@@ -324,7 +322,6 @@ static void test_ecall(void)
static void emcall(void)
{
unsigned long mask;
- struct lowcore *lc = (void *)0x0;
expect_ext_int();
ctl_set_bit(0, CTL0_EMERGENCY_SIGNAL);
@@ -332,7 +329,7 @@ static void emcall(void)
mask |= PSW_MASK_EXT;
load_psw_mask(mask);
set_flag(1);
- while (lc->ext_int_code != 0x1201) { mb(); }
+ while (lowcore.ext_int_code != 0x1201) { mb(); }
report_pass("received");
set_flag(1);
}
diff --git a/s390x/snippets/c/spec_ex.c b/s390x/snippets/c/spec_ex.c
index 71655ddb..40c170e6 100644
--- a/s390x/snippets/c/spec_ex.c
+++ b/s390x/snippets/c/spec_ex.c
@@ -10,12 +10,11 @@
__attribute__((section(".text"))) int main(void)
{
- struct lowcore *lowcore = (struct lowcore *) 0;
uint64_t bad_psw = 0;
/* PSW bit 12 has no name or meaning and must be 0 */
- lowcore->pgm_new_psw.mask = BIT(63 - 12);
- lowcore->pgm_new_psw.addr = 0xdeadbeee;
+ lowcore.pgm_new_psw.mask = BIT(63 - 12);
+ lowcore.pgm_new_psw.addr = 0xdeadbeee;
asm volatile ("lpsw %0" :: "Q"(bad_psw));
return 0;
}
--
2.33.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [kvm-unit-tests PATCH v2 2/2] s390x: Fix gcc 12 warning about array bounds
2022-05-20 14:05 [kvm-unit-tests PATCH v2 0/2] s390x: Avoid gcc 12 warnings Janis Schoetterl-Glausch
2022-05-20 14:05 ` [kvm-unit-tests PATCH v2 1/2] s390x: Introduce symbol for lowcore and use it Janis Schoetterl-Glausch
@ 2022-05-20 14:05 ` Janis Schoetterl-Glausch
2022-05-24 7:31 ` Claudio Imbrenda
2022-05-24 7:39 ` [kvm-unit-tests PATCH v2 0/2] s390x: Avoid gcc 12 warnings Claudio Imbrenda
2 siblings, 1 reply; 8+ messages in thread
From: Janis Schoetterl-Glausch @ 2022-05-20 14:05 UTC (permalink / raw)
To: Thomas Huth, Janosch Frank, Claudio Imbrenda
Cc: Janis Schoetterl-Glausch, David Hildenbrand, kvm, linux-s390
gcc 12 warns about pointer constant <4k dereference.
Silence the warning by using the extern lowcore symbol to derive the
pointers. This way gcc cannot conclude that the pointer is <4k.
Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
---
lib/s390x/asm/mem.h | 4 ++++
s390x/emulator.c | 5 +++--
s390x/skey.c | 2 +-
3 files changed, 8 insertions(+), 3 deletions(-)
diff --git a/lib/s390x/asm/mem.h b/lib/s390x/asm/mem.h
index 845c00cc..e7901fe0 100644
--- a/lib/s390x/asm/mem.h
+++ b/lib/s390x/asm/mem.h
@@ -7,6 +7,10 @@
*/
#ifndef _ASMS390X_MEM_H_
#define _ASMS390X_MEM_H_
+#include <asm/arch_def.h>
+
+/* pointer to 0 used to avoid compiler warnings */
+uint8_t *mem_all = (uint8_t *)&lowcore;
#define SKEY_ACC 0xf0
#define SKEY_FP 0x08
diff --git a/s390x/emulator.c b/s390x/emulator.c
index c9182ea4..afc3c213 100644
--- a/s390x/emulator.c
+++ b/s390x/emulator.c
@@ -12,6 +12,7 @@
#include <asm/cpacf.h>
#include <asm/interrupt.h>
#include <asm/float.h>
+#include <asm/mem.h>
#include <linux/compiler.h>
static inline void __test_spm_ipm(uint8_t cc, uint8_t key)
@@ -138,7 +139,7 @@ static __always_inline void __test_cpacf_invalid_parm(unsigned int opcode)
{
report_prefix_push("invalid parm address");
expect_pgm_int();
- __cpacf_query(opcode, (void *) -1);
+ __cpacf_query(opcode, (cpacf_mask_t *)&mem_all[-1]);
check_pgm_int_code(PGM_INT_CODE_ADDRESSING);
report_prefix_pop();
}
@@ -148,7 +149,7 @@ static __always_inline void __test_cpacf_protected_parm(unsigned int opcode)
report_prefix_push("protected parm address");
expect_pgm_int();
low_prot_enable();
- __cpacf_query(opcode, (void *) 8);
+ __cpacf_query(opcode, (cpacf_mask_t *)&mem_all[8]);
low_prot_disable();
check_pgm_int_code(PGM_INT_CODE_PROTECTION);
report_prefix_pop();
diff --git a/s390x/skey.c b/s390x/skey.c
index 32bf1070..42bf598c 100644
--- a/s390x/skey.c
+++ b/s390x/skey.c
@@ -349,7 +349,7 @@ static void test_set_prefix(void)
set_storage_key(pagebuf, 0x28, 0);
expect_pgm_int();
install_page(root, virt_to_pte_phys(root, pagebuf), 0);
- set_prefix_key_1((uint32_t *)2048);
+ set_prefix_key_1((uint32_t *)&mem_all[2048]);
install_page(root, 0, 0);
check_pgm_int_code(PGM_INT_CODE_PROTECTION);
report(get_prefix() == old_prefix, "did not set prefix");
--
2.33.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [kvm-unit-tests PATCH v2 2/2] s390x: Fix gcc 12 warning about array bounds
2022-05-20 14:05 ` [kvm-unit-tests PATCH v2 2/2] s390x: Fix gcc 12 warning about array bounds Janis Schoetterl-Glausch
@ 2022-05-24 7:31 ` Claudio Imbrenda
2022-05-24 9:35 ` Janis Schoetterl-Glausch
0 siblings, 1 reply; 8+ messages in thread
From: Claudio Imbrenda @ 2022-05-24 7:31 UTC (permalink / raw)
To: Janis Schoetterl-Glausch
Cc: Thomas Huth, Janosch Frank, David Hildenbrand, kvm, linux-s390
On Fri, 20 May 2022 16:05:46 +0200
Janis Schoetterl-Glausch <scgl@linux.ibm.com> wrote:
> gcc 12 warns about pointer constant <4k dereference.
> Silence the warning by using the extern lowcore symbol to derive the
> pointers. This way gcc cannot conclude that the pointer is <4k.
>
> Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
> ---
> lib/s390x/asm/mem.h | 4 ++++
> s390x/emulator.c | 5 +++--
> s390x/skey.c | 2 +-
> 3 files changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/lib/s390x/asm/mem.h b/lib/s390x/asm/mem.h
> index 845c00cc..e7901fe0 100644
> --- a/lib/s390x/asm/mem.h
> +++ b/lib/s390x/asm/mem.h
> @@ -7,6 +7,10 @@
> */
> #ifndef _ASMS390X_MEM_H_
> #define _ASMS390X_MEM_H_
> +#include <asm/arch_def.h>
> +
> +/* pointer to 0 used to avoid compiler warnings */
> +uint8_t *mem_all = (uint8_t *)&lowcore;
this is defined in a .h, so maybe it's better to declare it static?
although maybe you can simply declare a macro like this:
#define MEM(x) ((void *)((uint8_t *)&lowcore + (x)))
and then just use MEM(x)...
(please find a less generic name for MEM, though)
>
> #define SKEY_ACC 0xf0
> #define SKEY_FP 0x08
> diff --git a/s390x/emulator.c b/s390x/emulator.c
> index c9182ea4..afc3c213 100644
> --- a/s390x/emulator.c
> +++ b/s390x/emulator.c
> @@ -12,6 +12,7 @@
> #include <asm/cpacf.h>
> #include <asm/interrupt.h>
> #include <asm/float.h>
> +#include <asm/mem.h>
> #include <linux/compiler.h>
>
> static inline void __test_spm_ipm(uint8_t cc, uint8_t key)
> @@ -138,7 +139,7 @@ static __always_inline void __test_cpacf_invalid_parm(unsigned int opcode)
> {
> report_prefix_push("invalid parm address");
> expect_pgm_int();
> - __cpacf_query(opcode, (void *) -1);
> + __cpacf_query(opcode, (cpacf_mask_t *)&mem_all[-1]);
...for example here MEM(-1)
> check_pgm_int_code(PGM_INT_CODE_ADDRESSING);
> report_prefix_pop();
> }
> @@ -148,7 +149,7 @@ static __always_inline void __test_cpacf_protected_parm(unsigned int opcode)
> report_prefix_push("protected parm address");
> expect_pgm_int();
> low_prot_enable();
> - __cpacf_query(opcode, (void *) 8);
> + __cpacf_query(opcode, (cpacf_mask_t *)&mem_all[8]);
... MEM(8)
> low_prot_disable();
> check_pgm_int_code(PGM_INT_CODE_PROTECTION);
> report_prefix_pop();
> diff --git a/s390x/skey.c b/s390x/skey.c
> index 32bf1070..42bf598c 100644
> --- a/s390x/skey.c
> +++ b/s390x/skey.c
> @@ -349,7 +349,7 @@ static void test_set_prefix(void)
> set_storage_key(pagebuf, 0x28, 0);
> expect_pgm_int();
> install_page(root, virt_to_pte_phys(root, pagebuf), 0);
> - set_prefix_key_1((uint32_t *)2048);
> + set_prefix_key_1((uint32_t *)&mem_all[2048]);
... MEM(2048)
> install_page(root, 0, 0);
> check_pgm_int_code(PGM_INT_CODE_PROTECTION);
> report(get_prefix() == old_prefix, "did not set prefix");
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [kvm-unit-tests PATCH v2 0/2] s390x: Avoid gcc 12 warnings
2022-05-20 14:05 [kvm-unit-tests PATCH v2 0/2] s390x: Avoid gcc 12 warnings Janis Schoetterl-Glausch
2022-05-20 14:05 ` [kvm-unit-tests PATCH v2 1/2] s390x: Introduce symbol for lowcore and use it Janis Schoetterl-Glausch
2022-05-20 14:05 ` [kvm-unit-tests PATCH v2 2/2] s390x: Fix gcc 12 warning about array bounds Janis Schoetterl-Glausch
@ 2022-05-24 7:39 ` Claudio Imbrenda
2 siblings, 0 replies; 8+ messages in thread
From: Claudio Imbrenda @ 2022-05-24 7:39 UTC (permalink / raw)
To: Janis Schoetterl-Glausch
Cc: Thomas Huth, Janosch Frank, David Hildenbrand, kvm, linux-s390
On Fri, 20 May 2022 16:05:44 +0200
Janis Schoetterl-Glausch <scgl@linux.ibm.com> wrote:
> gcc 12 warns if a memory operand to inline asm points to memory in the
> first 4k bytes. However, in our case, these operands are fine, either
> because we actually want to use that memory, or expect and handle the
> resulting exception.
>
> v1 -> v2
> * replace mechanism, don't use pragmas, instead use an extern symbol so
> gcc cannot conclude that the pointer is <4k
this is a hack, but it's a nice hack
it gets rid of the compiler warning, and it also simplifies the
existing code.
>
> This new extern symbol refers to the lowcore. As a result, code
> generation for lowcore accesses becomes worse.
>
> Alternatives:
> * Don't use extern symbol for lowcore, just for problematic pointers
> * Hide value from gcc via inline asm
> * Disable the warning globally
> * Use memory clobber instead of memory output
> Use address in register input instead of memory input
> (may require WRITE_ONCE)
> * Don't use gcc 12.0, with newer versions --param=min-pagesize=0 might
> avoid the problem
>
> Janis Schoetterl-Glausch (2):
> s390x: Introduce symbol for lowcore and use it
> s390x: Fix gcc 12 warning about array bounds
>
> lib/s390x/asm/arch_def.h | 2 ++
> lib/s390x/asm/facility.h | 4 +--
> lib/s390x/asm/mem.h | 4 +++
> lib/s390x/css.h | 2 --
> lib/s390x/css_lib.c | 12 ++++----
> lib/s390x/fault.c | 10 +++----
> lib/s390x/interrupt.c | 61 +++++++++++++++++++-------------------
> lib/s390x/mmu.c | 3 +-
> s390x/flat.lds | 1 +
> s390x/snippets/c/flat.lds | 1 +
> s390x/css.c | 4 +--
> s390x/diag288.c | 4 +--
> s390x/edat.c | 5 ++--
> s390x/emulator.c | 15 +++++-----
> s390x/mvpg.c | 7 ++---
> s390x/sclp.c | 3 +-
> s390x/skey.c | 2 +-
> s390x/skrf.c | 11 +++----
> s390x/smp.c | 23 +++++++-------
> s390x/snippets/c/spec_ex.c | 5 ++--
> 20 files changed, 83 insertions(+), 96 deletions(-)
>
>
> base-commit: 8719e8326101c1be8256617caf5835b57e819339
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [kvm-unit-tests PATCH v2 1/2] s390x: Introduce symbol for lowcore and use it
2022-05-20 14:05 ` [kvm-unit-tests PATCH v2 1/2] s390x: Introduce symbol for lowcore and use it Janis Schoetterl-Glausch
@ 2022-05-24 7:42 ` Claudio Imbrenda
2022-06-03 13:12 ` Thomas Huth
1 sibling, 0 replies; 8+ messages in thread
From: Claudio Imbrenda @ 2022-05-24 7:42 UTC (permalink / raw)
To: Janis Schoetterl-Glausch
Cc: Thomas Huth, Janosch Frank, David Hildenbrand, kvm, linux-s390
On Fri, 20 May 2022 16:05:45 +0200
Janis Schoetterl-Glausch <scgl@linux.ibm.com> wrote:
> This gets rid of bunch of pointers pointing to the lowcore used in
> various places and replaces it with a unified way of addressing the
> lowcore.
> The new symbol is not a pointer. While this will lead to worse code
> generation (cannot use register 0 for addressing), that should not
> matter too much for kvm unit tests.
> The symbol also will be used to create pointers that the compiler cannot
> warn about as being outside the bounds of an array.
please also briefly explain that you are achieving all this with a small
change in the linker script
>
> Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
> ---
> lib/s390x/asm/arch_def.h | 2 ++
> lib/s390x/asm/facility.h | 4 +--
> lib/s390x/css.h | 2 --
> lib/s390x/css_lib.c | 12 ++++----
> lib/s390x/fault.c | 10 +++----
> lib/s390x/interrupt.c | 61 +++++++++++++++++++-------------------
> lib/s390x/mmu.c | 3 +-
> s390x/flat.lds | 1 +
> s390x/snippets/c/flat.lds | 1 +
> s390x/css.c | 4 +--
> s390x/diag288.c | 4 +--
> s390x/edat.c | 5 ++--
> s390x/emulator.c | 10 +++----
> s390x/mvpg.c | 7 ++---
> s390x/sclp.c | 3 +-
> s390x/skrf.c | 11 +++----
> s390x/smp.c | 23 +++++++-------
> s390x/snippets/c/spec_ex.c | 5 ++--
> 18 files changed, 75 insertions(+), 93 deletions(-)
>
> diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
> index 72553819..78b257b7 100644
> --- a/lib/s390x/asm/arch_def.h
> +++ b/lib/s390x/asm/arch_def.h
> @@ -145,6 +145,8 @@ struct lowcore {
> } __attribute__ ((__packed__));
> _Static_assert(sizeof(struct lowcore) == 0x1900, "Lowcore size");
>
> +extern struct lowcore lowcore;
> +
> #define PGM_INT_CODE_OPERATION 0x01
> #define PGM_INT_CODE_PRIVILEGED_OPERATION 0x02
> #define PGM_INT_CODE_EXECUTE 0x03
> diff --git a/lib/s390x/asm/facility.h b/lib/s390x/asm/facility.h
> index ef0fd037..49380203 100644
> --- a/lib/s390x/asm/facility.h
> +++ b/lib/s390x/asm/facility.h
> @@ -36,10 +36,8 @@ static inline void stfle(uint64_t *fac, unsigned int nb_doublewords)
>
> static inline void setup_facilities(void)
> {
> - struct lowcore *lc = NULL;
> -
> stfl();
> - memcpy(stfl_doublewords, &lc->stfl, sizeof(lc->stfl));
> + memcpy(stfl_doublewords, &lowcore.stfl, sizeof(lowcore.stfl));
> if (test_facility(7))
> stfle(stfl_doublewords, NB_STFL_DOUBLEWORDS);
> }
> diff --git a/lib/s390x/css.h b/lib/s390x/css.h
> index a6a68577..0a19324b 100644
> --- a/lib/s390x/css.h
> +++ b/lib/s390x/css.h
> @@ -9,8 +9,6 @@
> #ifndef _S390X_CSS_H_
> #define _S390X_CSS_H_
>
> -#define lowcore_ptr ((struct lowcore *)0x0)
> -
> /* subchannel ID bit 16 must always be one */
> #define SCHID_ONE 0x00010000
>
> diff --git a/lib/s390x/css_lib.c b/lib/s390x/css_lib.c
> index a9f5097f..b4d1f086 100644
> --- a/lib/s390x/css_lib.c
> +++ b/lib/s390x/css_lib.c
> @@ -357,11 +357,11 @@ void css_irq_io(void)
> int sid;
>
> report_prefix_push("Interrupt");
> - sid = lowcore_ptr->subsys_id_word;
> + sid = lowcore.subsys_id_word;
> /* Lowlevel set the SID as interrupt parameter. */
> - if (lowcore_ptr->io_int_param != sid) {
> + if (lowcore.io_int_param != sid) {
> report_fail("io_int_param: %x differs from subsys_id_word: %x",
> - lowcore_ptr->io_int_param, sid);
> + lowcore.io_int_param, sid);
> goto pop;
> }
> report_prefix_pop();
> @@ -387,7 +387,7 @@ void css_irq_io(void)
> }
> pop:
> report_prefix_pop();
> - lowcore_ptr->io_old_psw.mask &= ~PSW_MASK_WAIT;
> + lowcore.io_old_psw.mask &= ~PSW_MASK_WAIT;
> }
>
> int start_ccw1_chain(unsigned int sid, struct ccw1 *ccw)
> @@ -432,9 +432,9 @@ int wait_and_check_io_completion(int schid)
>
> report_prefix_push("check I/O completion");
>
> - if (lowcore_ptr->io_int_param != schid) {
> + if (lowcore.io_int_param != schid) {
> report_fail("interrupt parameter: expected %08x got %08x",
> - schid, lowcore_ptr->io_int_param);
> + schid, lowcore.io_int_param);
> ret = -1;
> goto end;
> }
> diff --git a/lib/s390x/fault.c b/lib/s390x/fault.c
> index d3ef00e4..efa62fcb 100644
> --- a/lib/s390x/fault.c
> +++ b/lib/s390x/fault.c
> @@ -13,8 +13,6 @@
> #include <asm/page.h>
> #include <fault.h>
>
> -static struct lowcore *lc = (struct lowcore *)0x0;
> -
> /* Decodes the protection exceptions we'll most likely see */
> static void print_decode_pgm_prot(uint64_t teid)
> {
> @@ -37,7 +35,7 @@ static void print_decode_pgm_prot(uint64_t teid)
> void print_decode_teid(uint64_t teid)
> {
> int asce_id = teid & 3;
> - bool dat = lc->pgm_old_psw.mask & PSW_MASK_DAT;
> + bool dat = lowcore.pgm_old_psw.mask & PSW_MASK_DAT;
>
> printf("Memory exception information:\n");
> printf("DAT: %s\n", dat ? "on" : "off");
> @@ -58,15 +56,15 @@ void print_decode_teid(uint64_t teid)
> break;
> }
>
> - if (lc->pgm_int_code == PGM_INT_CODE_PROTECTION)
> + if (lowcore.pgm_int_code == PGM_INT_CODE_PROTECTION)
> print_decode_pgm_prot(teid);
>
> /*
> * If teid bit 61 is off for these two exception the reported
> * address is unpredictable.
> */
> - if ((lc->pgm_int_code == PGM_INT_CODE_SECURE_STOR_ACCESS ||
> - lc->pgm_int_code == PGM_INT_CODE_SECURE_STOR_VIOLATION) &&
> + if ((lowcore.pgm_int_code == PGM_INT_CODE_SECURE_STOR_ACCESS ||
> + lowcore.pgm_int_code == PGM_INT_CODE_SECURE_STOR_VIOLATION) &&
> !test_bit_inv(61, &teid)) {
> printf("Address: %lx, unpredictable\n ", teid & PAGE_MASK);
> return;
> diff --git a/lib/s390x/interrupt.c b/lib/s390x/interrupt.c
> index 27d3b767..6da20c44 100644
> --- a/lib/s390x/interrupt.c
> +++ b/lib/s390x/interrupt.c
> @@ -18,20 +18,19 @@
> static bool pgm_int_expected;
> static bool ext_int_expected;
> static void (*pgm_cleanup_func)(void);
> -static struct lowcore *lc;
>
> void expect_pgm_int(void)
> {
> pgm_int_expected = true;
> - lc->pgm_int_code = 0;
> - lc->trans_exc_id = 0;
> + lowcore.pgm_int_code = 0;
> + lowcore.trans_exc_id = 0;
> mb();
> }
>
> void expect_ext_int(void)
> {
> ext_int_expected = true;
> - lc->ext_int_code = 0;
> + lowcore.ext_int_code = 0;
> mb();
> }
>
> @@ -40,9 +39,9 @@ uint16_t clear_pgm_int(void)
> uint16_t code;
>
> mb();
> - code = lc->pgm_int_code;
> - lc->pgm_int_code = 0;
> - lc->trans_exc_id = 0;
> + code = lowcore.pgm_int_code;
> + lowcore.pgm_int_code = 0;
> + lowcore.trans_exc_id = 0;
> pgm_int_expected = false;
> return code;
> }
> @@ -50,9 +49,9 @@ uint16_t clear_pgm_int(void)
> void check_pgm_int_code(uint16_t code)
> {
> mb();
> - report(code == lc->pgm_int_code,
> + report(code == lowcore.pgm_int_code,
> "Program interrupt: expected(%d) == received(%d)", code,
> - lc->pgm_int_code);
> + lowcore.pgm_int_code);
> }
>
> void register_pgm_cleanup_func(void (*f)(void))
> @@ -63,29 +62,29 @@ void register_pgm_cleanup_func(void (*f)(void))
> static void fixup_pgm_int(struct stack_frame_int *stack)
> {
> /* If we have an error on SIE we directly move to sie_exit */
> - if (lc->pgm_old_psw.addr >= (uint64_t)&sie_entry &&
> - lc->pgm_old_psw.addr <= (uint64_t)&sie_exit) {
> - lc->pgm_old_psw.addr = (uint64_t)&sie_exit;
> + if (lowcore.pgm_old_psw.addr >= (uint64_t)&sie_entry &&
> + lowcore.pgm_old_psw.addr <= (uint64_t)&sie_exit) {
> + lowcore.pgm_old_psw.addr = (uint64_t)&sie_exit;
> }
>
> - switch (lc->pgm_int_code) {
> + switch (lowcore.pgm_int_code) {
> case PGM_INT_CODE_PRIVILEGED_OPERATION:
> /* Normal operation is in supervisor state, so this exception
> * was produced intentionally and we should return to the
> * supervisor state.
> */
> - lc->pgm_old_psw.mask &= ~PSW_MASK_PSTATE;
> + lowcore.pgm_old_psw.mask &= ~PSW_MASK_PSTATE;
> break;
> case PGM_INT_CODE_PROTECTION:
> /* Handling for iep.c test case. */
> - if (prot_is_iep(lc->trans_exc_id))
> + if (prot_is_iep(lowcore.trans_exc_id))
> /*
> * We branched to the instruction that caused
> * the exception so we can use the return
> * address in GR14 to jump back and continue
> * executing test code.
> */
> - lc->pgm_old_psw.addr = stack->grs0[12];
> + lowcore.pgm_old_psw.addr = stack->grs0[12];
> break;
> case PGM_INT_CODE_SEGMENT_TRANSLATION:
> case PGM_INT_CODE_PAGE_TRANSLATION:
> @@ -122,14 +121,14 @@ static void fixup_pgm_int(struct stack_frame_int *stack)
> /* The interrupt was nullified, the old PSW points at the
> * responsible instruction. Forward the PSW so we don't loop.
> */
> - lc->pgm_old_psw.addr += lc->pgm_int_id;
> + lowcore.pgm_old_psw.addr += lowcore.pgm_int_id;
> }
> /* suppressed/terminated/completed point already at the next address */
> }
>
> static void print_storage_exception_information(void)
> {
> - switch (lc->pgm_int_code) {
> + switch (lowcore.pgm_int_code) {
> case PGM_INT_CODE_PROTECTION:
> case PGM_INT_CODE_PAGE_TRANSLATION:
> case PGM_INT_CODE_SEGMENT_TRANSLATION:
> @@ -140,7 +139,7 @@ static void print_storage_exception_information(void)
> case PGM_INT_CODE_SECURE_STOR_ACCESS:
> case PGM_INT_CODE_NON_SECURE_STOR_ACCESS:
> case PGM_INT_CODE_SECURE_STOR_VIOLATION:
> - print_decode_teid(lc->trans_exc_id);
> + print_decode_teid(lowcore.trans_exc_id);
> break;
> }
> }
> @@ -165,13 +164,13 @@ static void print_pgm_info(struct stack_frame_int *stack)
> {
> bool in_sie;
>
> - in_sie = (lc->pgm_old_psw.addr >= (uintptr_t)sie_entry &&
> - lc->pgm_old_psw.addr <= (uintptr_t)sie_exit);
> + in_sie = (lowcore.pgm_old_psw.addr >= (uintptr_t)sie_entry &&
> + lowcore.pgm_old_psw.addr <= (uintptr_t)sie_exit);
>
> printf("\n");
> printf("Unexpected program interrupt %s: %#x on cpu %d at %#lx, ilen %d\n",
> in_sie ? "in SIE" : "",
> - lc->pgm_int_code, stap(), lc->pgm_old_psw.addr, lc->pgm_int_id);
> + lowcore.pgm_int_code, stap(), lowcore.pgm_old_psw.addr, lowcore.pgm_int_id);
> print_int_regs(stack);
> dump_stack();
>
> @@ -201,13 +200,13 @@ void handle_pgm_int(struct stack_frame_int *stack)
> void handle_ext_int(struct stack_frame_int *stack)
> {
> if (!ext_int_expected &&
> - lc->ext_int_code != EXT_IRQ_SERVICE_SIG) {
> + lowcore.ext_int_code != EXT_IRQ_SERVICE_SIG) {
> report_abort("Unexpected external call interrupt (code %#x): on cpu %d at %#lx",
> - lc->ext_int_code, stap(), lc->ext_old_psw.addr);
> + lowcore.ext_int_code, stap(), lowcore.ext_old_psw.addr);
> return;
> }
>
> - if (lc->ext_int_code == EXT_IRQ_SERVICE_SIG) {
> + if (lowcore.ext_int_code == EXT_IRQ_SERVICE_SIG) {
> stack->crs[0] &= ~(1UL << 9);
> sclp_handle_ext();
> } else {
> @@ -215,13 +214,13 @@ void handle_ext_int(struct stack_frame_int *stack)
> }
>
> if (!(stack->crs[0] & CR0_EXTM_MASK))
> - lc->ext_old_psw.mask &= ~PSW_MASK_EXT;
> + lowcore.ext_old_psw.mask &= ~PSW_MASK_EXT;
> }
>
> void handle_mcck_int(void)
> {
> report_abort("Unexpected machine check interrupt: on cpu %d at %#lx",
> - stap(), lc->mcck_old_psw.addr);
> + stap(), lowcore.mcck_old_psw.addr);
> }
>
> static void (*io_int_func)(void);
> @@ -232,7 +231,7 @@ void handle_io_int(void)
> return io_int_func();
>
> report_abort("Unexpected io interrupt: on cpu %d at %#lx",
> - stap(), lc->io_old_psw.addr);
> + stap(), lowcore.io_old_psw.addr);
> }
>
> int register_io_int_func(void (*f)(void))
> @@ -253,14 +252,14 @@ int unregister_io_int_func(void (*f)(void))
>
> void handle_svc_int(void)
> {
> - uint16_t code = lc->svc_int_code;
> + uint16_t code = lowcore.svc_int_code;
>
> switch (code) {
> case SVC_LEAVE_PSTATE:
> - lc->svc_old_psw.mask &= ~PSW_MASK_PSTATE;
> + lowcore.svc_old_psw.mask &= ~PSW_MASK_PSTATE;
> break;
> default:
> report_abort("Unexpected supervisor call interrupt: code %#x on cpu %d at %#lx",
> - code, stap(), lc->svc_old_psw.addr);
> + code, stap(), lowcore.svc_old_psw.addr);
> }
> }
> diff --git a/lib/s390x/mmu.c b/lib/s390x/mmu.c
> index 6f9e6502..c9f8754c 100644
> --- a/lib/s390x/mmu.c
> +++ b/lib/s390x/mmu.c
> @@ -43,7 +43,6 @@ void configure_dat(int enable)
>
> static void mmu_enable(pgd_t *pgtable)
> {
> - struct lowcore *lc = NULL;
> const uint64_t asce = __pa(pgtable) | ASCE_DT_REGION1 |
> REGION_TABLE_LENGTH;
>
> @@ -55,7 +54,7 @@ static void mmu_enable(pgd_t *pgtable)
> configure_dat(1);
>
> /* we can now also use DAT unconditionally in our PGM handler */
> - lc->pgm_new_psw.mask |= PSW_MASK_DAT;
> + lowcore.pgm_new_psw.mask |= PSW_MASK_DAT;
> }
>
> /*
> diff --git a/s390x/flat.lds b/s390x/flat.lds
> index 86dffacd..de9da1a8 100644
> --- a/s390x/flat.lds
> +++ b/s390x/flat.lds
> @@ -7,6 +7,7 @@ SECTIONS
> * address 0x10000 (cstart64.S .init).
> */
> . = 0;
> + lowcore = .;
> LONG(0x00080000)
> LONG(0x80010000)
> /* Restart new PSW for booting via PSW restart. */
> diff --git a/s390x/snippets/c/flat.lds b/s390x/snippets/c/flat.lds
> index 59974b38..260ab1c4 100644
> --- a/s390x/snippets/c/flat.lds
> +++ b/s390x/snippets/c/flat.lds
> @@ -7,6 +7,7 @@ SECTIONS
> * address 0x4000 (cstart.S .init).
> */
> . = 0;
> + lowcore = .;
> LONG(0x00080000)
> LONG(0x80004000)
> /* Restart new PSW for booting via PSW restart. */
> diff --git a/s390x/css.c b/s390x/css.c
> index fabe5237..4b6e31b3 100644
> --- a/s390x/css.c
> +++ b/s390x/css.c
> @@ -74,7 +74,7 @@ static void test_sense(void)
> return;
> }
>
> - lowcore_ptr->io_int_param = 0;
> + lowcore.io_int_param = 0;
>
> senseid = alloc_io_mem(sizeof(*senseid), 0);
> if (!senseid) {
> @@ -143,7 +143,7 @@ static void sense_id(void)
> static void css_init(void)
> {
> assert(register_io_int_func(css_irq_io) == 0);
> - lowcore_ptr->io_int_param = 0;
> + lowcore.io_int_param = 0;
>
> report(get_chsc_scsc(), "Store Channel Characteristics");
> }
> diff --git a/s390x/diag288.c b/s390x/diag288.c
> index 072c04a5..e414865b 100644
> --- a/s390x/diag288.c
> +++ b/s390x/diag288.c
> @@ -12,8 +12,6 @@
> #include <asm/asm-offsets.h>
> #include <asm/interrupt.h>
>
> -struct lowcore *lc = (struct lowcore *)0x0;
> -
> #define CODE_INIT 0
> #define CODE_CHANGE 1
> #define CODE_CANCEL 2
> @@ -92,7 +90,7 @@ static void test_bite(void)
> load_psw_mask(mask);
>
> /* Arm watchdog */
> - lc->restart_new_psw.mask = extract_psw_mask() & ~PSW_MASK_EXT;
> + lowcore.restart_new_psw.mask = extract_psw_mask() & ~PSW_MASK_EXT;
> diag288(CODE_INIT, 15, ACTION_RESTART);
> asm volatile(" larl %r0, 1f\n"
> " stg %r0, 424\n"
> diff --git a/s390x/edat.c b/s390x/edat.c
> index c3bee0c8..c6c25042 100644
> --- a/s390x/edat.c
> +++ b/s390x/edat.c
> @@ -23,7 +23,6 @@
> static uint8_t prefix_buf[LC_SIZE] __attribute__((aligned(LC_SIZE)));
> static unsigned int tmp[1024] __attribute__((aligned(PAGE_SIZE)));
> static void *root, *mem, *m;
> -static struct lowcore *lc;
> volatile unsigned int *p;
>
> /*
> @@ -34,10 +33,10 @@ static bool check_pgm_prot(void *ptr)
> {
> union teid teid;
>
> - if (lc->pgm_int_code != PGM_INT_CODE_PROTECTION)
> + if (lowcore.pgm_int_code != PGM_INT_CODE_PROTECTION)
> return false;
>
> - teid.val = lc->trans_exc_id;
> + teid.val = lowcore.trans_exc_id;
>
> /*
> * depending on the presence of the ESOP feature, the rest of the
> diff --git a/s390x/emulator.c b/s390x/emulator.c
> index b2787a55..c9182ea4 100644
> --- a/s390x/emulator.c
> +++ b/s390x/emulator.c
> @@ -14,8 +14,6 @@
> #include <asm/float.h>
> #include <linux/compiler.h>
>
> -struct lowcore *lc = NULL;
> -
> static inline void __test_spm_ipm(uint8_t cc, uint8_t key)
> {
> uint64_t in = (cc << 28) | (key << 24);
> @@ -262,7 +260,7 @@ static void test_prno(void)
> static void test_dxc(void)
> {
> /* DXC (0xff) is to be stored in LC and FPC on a trap (CRT) with AFP */
> - lc->dxc_vxc = 0x12345678;
> + lowcore.dxc_vxc = 0x12345678;
> set_fpc_dxc(0);
>
> report_prefix_push("afp");
> @@ -271,12 +269,12 @@ static void test_dxc(void)
> : : "r"(0) : "memory");
> check_pgm_int_code(PGM_INT_CODE_DATA);
>
> - report(lc->dxc_vxc == 0xff, "dxc in LC");
> + report(lowcore.dxc_vxc == 0xff, "dxc in LC");
> report(get_fpc_dxc() == 0xff, "dxc in FPC");
> report_prefix_pop();
>
> /* DXC (0xff) is to be stored in LC only on a trap (CRT) without AFP */
> - lc->dxc_vxc = 0x12345678;
> + lowcore.dxc_vxc = 0x12345678;
> set_fpc_dxc(0);
>
> report_prefix_push("no-afp");
> @@ -288,7 +286,7 @@ static void test_dxc(void)
> afp_enable();
> check_pgm_int_code(PGM_INT_CODE_DATA);
>
> - report(lc->dxc_vxc == 0xff, "dxc in LC");
> + report(lowcore.dxc_vxc == 0xff, "dxc in LC");
> report(get_fpc_dxc() == 0, "dxc not in FPC");
> report_prefix_pop();
> }
> diff --git a/s390x/mvpg.c b/s390x/mvpg.c
> index 04e5218f..296338d4 100644
> --- a/s390x/mvpg.c
> +++ b/s390x/mvpg.c
> @@ -33,7 +33,6 @@
>
> static uint8_t source[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
> static uint8_t buffer[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
> -static struct lowcore * const lc;
>
> /* Keep track of fresh memory */
> static uint8_t *fresh;
> @@ -87,7 +86,7 @@ static int page_ok(const uint8_t *p)
> */
> static inline bool check_oai(void)
> {
> - return *(uint8_t *)(lc->pgm_old_psw.addr - 1) == lc->op_acc_id;
> + return *(uint8_t *)(lowcore.pgm_old_psw.addr - 1) == lowcore.op_acc_id;
> }
>
> static void test_exceptions(void)
> @@ -216,7 +215,7 @@ static void test_mmu_prot(void)
>
> report_prefix_push("source invalid");
> protect_page(source, PAGE_ENTRY_I);
> - lc->op_acc_id = 0;
> + lowcore.op_acc_id = 0;
> expect_pgm_int();
> mvpg(0, fresh, source);
> report(clear_pgm_int() == PGM_INT_CODE_PAGE_TRANSLATION, "exception");
> @@ -227,7 +226,7 @@ static void test_mmu_prot(void)
>
> report_prefix_push("destination invalid");
> protect_page(fresh, PAGE_ENTRY_I);
> - lc->op_acc_id = 0;
> + lowcore.op_acc_id = 0;
> expect_pgm_int();
> mvpg(0, fresh, source);
> report(clear_pgm_int() == PGM_INT_CODE_PAGE_TRANSLATION, "exception");
> diff --git a/s390x/sclp.c b/s390x/sclp.c
> index 73d722fb..1abb9029 100644
> --- a/s390x/sclp.c
> +++ b/s390x/sclp.c
> @@ -31,7 +31,6 @@ static union {
> WriteEventData data;
> } sccb_template;
> static uint32_t valid_code; /* valid command code for READ SCP INFO */
> -static struct lowcore *lc;
>
> /**
> * Perform one service call, handling exceptions and interrupts.
> @@ -43,7 +42,7 @@ static int sclp_service_call_test(unsigned int command, void *sccb)
> sclp_mark_busy();
> sclp_setup_int();
> cc = servc(command, __pa(sccb));
> - if (lc->pgm_int_code) {
> + if (lowcore.pgm_int_code) {
> sclp_handle_ext();
> return 0;
> }
> diff --git a/s390x/skrf.c b/s390x/skrf.c
> index b9a2e902..1a811894 100644
> --- a/s390x/skrf.c
> +++ b/s390x/skrf.c
> @@ -123,17 +123,15 @@ static void set_flag(int val)
>
> static void ecall_cleanup(void)
> {
> - struct lowcore *lc = (void *)0x0;
> -
> - lc->ext_new_psw.mask = PSW_MASK_64;
> - lc->sw_int_crs[0] = BIT_ULL(CTL0_AFP);
> + lowcore.ext_new_psw.mask = PSW_MASK_64;
> + lowcore.sw_int_crs[0] = BIT_ULL(CTL0_AFP);
>
> /*
> * PGM old contains the ext new PSW, we need to clean it up,
> * so we don't get a special operation exception on the lpswe
> * of pgm old.
> */
> - lc->pgm_old_psw.mask = PSW_MASK_64;
> + lowcore.pgm_old_psw.mask = PSW_MASK_64;
>
> check_pgm_int_code(PGM_INT_CODE_SPECIFICATION);
> set_flag(1);
> @@ -142,13 +140,12 @@ static void ecall_cleanup(void)
> /* Set a key into the external new psw mask and open external call masks */
> static void ecall_setup(void)
> {
> - struct lowcore *lc = (void *)0x0;
> uint64_t mask;
>
> register_pgm_cleanup_func(ecall_cleanup);
> expect_pgm_int();
> /* Put a skey into the ext new psw */
> - lc->ext_new_psw.mask = 0x00F0000000000000UL | PSW_MASK_64;
> + lowcore.ext_new_psw.mask = 0x00F0000000000000UL | PSW_MASK_64;
> /* Open up ext masks */
> ctl_set_bit(0, CTL0_EXTERNAL_CALL);
> mask = extract_psw_mask();
> diff --git a/s390x/smp.c b/s390x/smp.c
> index de3aba71..6d474d0d 100644
> --- a/s390x/smp.c
> +++ b/s390x/smp.c
> @@ -155,28 +155,27 @@ static void test_stop(void)
> static void test_stop_store_status(void)
> {
> struct cpu *cpu = smp_cpu_from_idx(1);
> - struct lowcore *lc = (void *)0x0;
>
> report_prefix_push("stop store status");
> report_prefix_push("running");
> smp_cpu_restart(1);
> - lc->prefix_sa = 0;
> - lc->grs_sa[15] = 0;
> + lowcore.prefix_sa = 0;
> + lowcore.grs_sa[15] = 0;
> smp_cpu_stop_store_status(1);
> mb();
> report(smp_cpu_stopped(1), "cpu stopped");
> - report(lc->prefix_sa == (uint32_t)(uintptr_t)cpu->lowcore, "prefix");
> - report(lc->grs_sa[15], "stack");
> + report(lowcore.prefix_sa == (uint32_t)(uintptr_t)cpu->lowcore, "prefix");
> + report(lowcore.grs_sa[15], "stack");
> report_prefix_pop();
>
> report_prefix_push("stopped");
> - lc->prefix_sa = 0;
> - lc->grs_sa[15] = 0;
> + lowcore.prefix_sa = 0;
> + lowcore.grs_sa[15] = 0;
> smp_cpu_stop_store_status(1);
> mb();
> report(smp_cpu_stopped(1), "cpu stopped");
> - report(lc->prefix_sa == (uint32_t)(uintptr_t)cpu->lowcore, "prefix");
> - report(lc->grs_sa[15], "stack");
> + report(lowcore.prefix_sa == (uint32_t)(uintptr_t)cpu->lowcore, "prefix");
> + report(lowcore.grs_sa[15], "stack");
> report_prefix_pop();
>
> report_prefix_pop();
> @@ -290,7 +289,6 @@ static void test_set_prefix(void)
> static void ecall(void)
> {
> unsigned long mask;
> - struct lowcore *lc = (void *)0x0;
>
> expect_ext_int();
> ctl_set_bit(0, CTL0_EXTERNAL_CALL);
> @@ -298,7 +296,7 @@ static void ecall(void)
> mask |= PSW_MASK_EXT;
> load_psw_mask(mask);
> set_flag(1);
> - while (lc->ext_int_code != 0x1202) { mb(); }
> + while (lowcore.ext_int_code != 0x1202) { mb(); }
> report_pass("received");
> set_flag(1);
> }
> @@ -324,7 +322,6 @@ static void test_ecall(void)
> static void emcall(void)
> {
> unsigned long mask;
> - struct lowcore *lc = (void *)0x0;
>
> expect_ext_int();
> ctl_set_bit(0, CTL0_EMERGENCY_SIGNAL);
> @@ -332,7 +329,7 @@ static void emcall(void)
> mask |= PSW_MASK_EXT;
> load_psw_mask(mask);
> set_flag(1);
> - while (lc->ext_int_code != 0x1201) { mb(); }
> + while (lowcore.ext_int_code != 0x1201) { mb(); }
> report_pass("received");
> set_flag(1);
> }
> diff --git a/s390x/snippets/c/spec_ex.c b/s390x/snippets/c/spec_ex.c
> index 71655ddb..40c170e6 100644
> --- a/s390x/snippets/c/spec_ex.c
> +++ b/s390x/snippets/c/spec_ex.c
> @@ -10,12 +10,11 @@
>
> __attribute__((section(".text"))) int main(void)
> {
> - struct lowcore *lowcore = (struct lowcore *) 0;
> uint64_t bad_psw = 0;
>
> /* PSW bit 12 has no name or meaning and must be 0 */
> - lowcore->pgm_new_psw.mask = BIT(63 - 12);
> - lowcore->pgm_new_psw.addr = 0xdeadbeee;
> + lowcore.pgm_new_psw.mask = BIT(63 - 12);
> + lowcore.pgm_new_psw.addr = 0xdeadbeee;
> asm volatile ("lpsw %0" :: "Q"(bad_psw));
> return 0;
> }
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [kvm-unit-tests PATCH v2 2/2] s390x: Fix gcc 12 warning about array bounds
2022-05-24 7:31 ` Claudio Imbrenda
@ 2022-05-24 9:35 ` Janis Schoetterl-Glausch
0 siblings, 0 replies; 8+ messages in thread
From: Janis Schoetterl-Glausch @ 2022-05-24 9:35 UTC (permalink / raw)
To: Claudio Imbrenda
Cc: Thomas Huth, Janosch Frank, David Hildenbrand, kvm, linux-s390
On 5/24/22 09:31, Claudio Imbrenda wrote:
> On Fri, 20 May 2022 16:05:46 +0200
> Janis Schoetterl-Glausch <scgl@linux.ibm.com> wrote:
>
>> gcc 12 warns about pointer constant <4k dereference.
>> Silence the warning by using the extern lowcore symbol to derive the
>> pointers. This way gcc cannot conclude that the pointer is <4k.
>>
>> Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
>> ---
>> lib/s390x/asm/mem.h | 4 ++++
>> s390x/emulator.c | 5 +++--
>> s390x/skey.c | 2 +-
>> 3 files changed, 8 insertions(+), 3 deletions(-)
>>
>> diff --git a/lib/s390x/asm/mem.h b/lib/s390x/asm/mem.h
>> index 845c00cc..e7901fe0 100644
>> --- a/lib/s390x/asm/mem.h
>> +++ b/lib/s390x/asm/mem.h
>> @@ -7,6 +7,10 @@
>> */
>> #ifndef _ASMS390X_MEM_H_
>> #define _ASMS390X_MEM_H_
>> +#include <asm/arch_def.h>
>> +
>> +/* pointer to 0 used to avoid compiler warnings */
>> +uint8_t *mem_all = (uint8_t *)&lowcore;
>
> this is defined in a .h, so maybe it's better to declare it static?
>
>
> although maybe you can simply declare a macro like this:
>
> #define MEM(x) ((void *)((uint8_t *)&lowcore + (x)))
>
> and then just use MEM(x)...
>
> (please find a less generic name for MEM, though)
MEM_ALL
MEM_ABS
MEM_OPAQUE
OPAQUE_PTR
Suggestions welcome, the last would be my favorite.
[...]
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [kvm-unit-tests PATCH v2 1/2] s390x: Introduce symbol for lowcore and use it
2022-05-20 14:05 ` [kvm-unit-tests PATCH v2 1/2] s390x: Introduce symbol for lowcore and use it Janis Schoetterl-Glausch
2022-05-24 7:42 ` Claudio Imbrenda
@ 2022-06-03 13:12 ` Thomas Huth
1 sibling, 0 replies; 8+ messages in thread
From: Thomas Huth @ 2022-06-03 13:12 UTC (permalink / raw)
To: Janis Schoetterl-Glausch, Janosch Frank, Claudio Imbrenda
Cc: David Hildenbrand, kvm, linux-s390
On 20/05/2022 16.05, Janis Schoetterl-Glausch wrote:
> This gets rid of bunch of pointers pointing to the lowcore used in
> various places and replaces it with a unified way of addressing the
> lowcore.
> The new symbol is not a pointer. While this will lead to worse code
> generation (cannot use register 0 for addressing), that should not
> matter too much for kvm unit tests.
> The symbol also will be used to create pointers that the compiler cannot
> warn about as being outside the bounds of an array.
>
> Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2022-06-03 13:12 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-05-20 14:05 [kvm-unit-tests PATCH v2 0/2] s390x: Avoid gcc 12 warnings Janis Schoetterl-Glausch
2022-05-20 14:05 ` [kvm-unit-tests PATCH v2 1/2] s390x: Introduce symbol for lowcore and use it Janis Schoetterl-Glausch
2022-05-24 7:42 ` Claudio Imbrenda
2022-06-03 13:12 ` Thomas Huth
2022-05-20 14:05 ` [kvm-unit-tests PATCH v2 2/2] s390x: Fix gcc 12 warning about array bounds Janis Schoetterl-Glausch
2022-05-24 7:31 ` Claudio Imbrenda
2022-05-24 9:35 ` Janis Schoetterl-Glausch
2022-05-24 7:39 ` [kvm-unit-tests PATCH v2 0/2] s390x: Avoid gcc 12 warnings Claudio Imbrenda
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