s390/kernel: introduce .dma sections

With a relocatable kernel that could reside at any place in memory, code
and data that has to stay below 2 GB needs special handling.

This patch introduces .dma sections for such text, data and ex_table.
The sections will be part of the decompressor kernel, so they will not
be relocated and stay below 2 GB. Their location is passed over to the
decompressed / relocated kernel via the .boot.preserved.data section.

The duald and aste for control register setup also need to stay below
2 GB, so move the setup code from arch/s390/kernel/head64.S to
arch/s390/boot/head.S. The duct and linkage_stack could reside above
2 GB, but their content has to be preserved for the decompresed kernel,
so they are also moved into the .dma section.

The start and end address of the .dma sections is added to vmcoreinfo,
for crash support, to help debugging in case the kernel crashed there.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Reviewed-by: Philipp Rudo <prudo@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

11 files changed, 30 insertions, 168 deletions

diff --git a/arch/s390/kernel/base.S b/arch/s390/kernel/base.S
index f268fca67e82..d6ee5978e273 100644
--- a/arch/s390/kernel/base.S
+++ b/arch/s390/kernel/base.S
@@ -79,71 +79,3 @@ disabled_wait_psw:
 s390_base_pgm_handler_fn:
 	.quad	0
 	.previous
-
-#
-# Calls diag 308 subcode 1 and continues execution
-#
-ENTRY(diag308_reset)
-	larl	%r4,.Lctlregs		# Save control registers
-	stctg	%c0,%c15,0(%r4)
-	lg	%r2,0(%r4)		# Disable lowcore protection
-	nilh	%r2,0xefff
-	larl	%r4,.Lctlreg0
-	stg	%r2,0(%r4)
-	lctlg	%c0,%c0,0(%r4)
-	larl	%r4,.Lfpctl		# Floating point control register
-	stfpc	0(%r4)
-	larl	%r4,.Lprefix		# Save prefix register
-	stpx	0(%r4)
-	larl	%r4,.Lprefix_zero	# Set prefix register to 0
-	spx	0(%r4)
-	larl	%r4,.Lcontinue_psw	# Save PSW flags
-	epsw	%r2,%r3
-	stm	%r2,%r3,0(%r4)
-	larl	%r4,.Lrestart_psw	# Setup restart PSW at absolute 0
-	lghi	%r3,0
-	lg	%r4,0(%r4)		# Save PSW
-	sturg	%r4,%r3			# Use sturg, because of large pages
-	lghi	%r1,1
-	lghi	%r0,0
-	diag	%r0,%r1,0x308
-.Lrestart_part2:
-	lhi	%r0,0			# Load r0 with zero
-	lhi	%r1,2			# Use mode 2 = ESAME (dump)
-	sigp	%r1,%r0,SIGP_SET_ARCHITECTURE	# Switch to ESAME mode
-	sam64				# Switch to 64 bit addressing mode
-	larl	%r4,.Lctlregs		# Restore control registers
-	lctlg	%c0,%c15,0(%r4)
-	larl	%r4,.Lfpctl		# Restore floating point ctl register
-	lfpc	0(%r4)
-	larl	%r4,.Lprefix		# Restore prefix register
-	spx	0(%r4)
-	larl	%r4,.Lcontinue_psw	# Restore PSW flags
-	lpswe	0(%r4)
-.Lcontinue:
-	BR_EX	%r14
-.align 16
-.Lrestart_psw:
-	.long	0x00080000,0x80000000 + .Lrestart_part2
-
-	.section .data..nosave,"aw",@progbits
-.align 8
-.Lcontinue_psw:
-	.quad	0,.Lcontinue
-	.previous
-
-	.section .bss
-.align 8
-.Lctlreg0:
-	.quad	0
-.Lctlregs:
-	.rept	16
-	.quad	0
-	.endr
-.Lfpctl:
-	.long	0
-.Lprefix:
-	.long	0
-.Lprefix_zero:
-	.long	0
-	.previous
diff --git a/arch/s390/kernel/diag.c b/arch/s390/kernel/diag.c
index 7edaa733a77f..e9dac9a24d3f 100644
--- a/arch/s390/kernel/diag.c
+++ b/arch/s390/kernel/diag.c
@@ -13,6 +13,7 @@
 #include <linux/debugfs.h>
 #include <asm/diag.h>
 #include <asm/trace/diag.h>
+#include <asm/sections.h>
 
 struct diag_stat {
 	unsigned int counter[NR_DIAG_STAT];
@@ -49,6 +50,9 @@ static const struct diag_desc diag_map[NR_DIAG_STAT] = {
 	[DIAG_STAT_X500] = { .code = 0x500, .name = "Virtio Service" },
 };
 
+struct diag_ops __bootdata_preserved(diag_dma_ops);
+struct diag210 *__bootdata_preserved(__diag210_tmp_dma);
+
 static int show_diag_stat(struct seq_file *m, void *v)
 {
 	struct diag_stat *stat;
@@ -139,30 +143,10 @@ EXPORT_SYMBOL(diag_stat_inc_norecursion);
 /*
  * Diagnose 14: Input spool file manipulation
  */
-static inline int __diag14(unsigned long rx, unsigned long ry1,
-			   unsigned long subcode)
-{
-	register unsigned long _ry1 asm("2") = ry1;
-	register unsigned long _ry2 asm("3") = subcode;
-	int rc = 0;
-
-	asm volatile(
-		"   sam31\n"
-		"   diag    %2,2,0x14\n"
-		"   sam64\n"
-		"   ipm     %0\n"
-		"   srl     %0,28\n"
-		: "=d" (rc), "+d" (_ry2)
-		: "d" (rx), "d" (_ry1)
-		: "cc");
-
-	return rc;
-}
-
 int diag14(unsigned long rx, unsigned long ry1, unsigned long subcode)
 {
 	diag_stat_inc(DIAG_STAT_X014);
-	return __diag14(rx, ry1, subcode);
+	return diag_dma_ops.diag14(rx, ry1, subcode);
 }
 EXPORT_SYMBOL(diag14);
 
@@ -195,30 +179,17 @@ EXPORT_SYMBOL(diag204);
  */
 int diag210(struct diag210 *addr)
 {
-	/*
-	 * diag 210 needs its data below the 2GB border, so we
-	 * use a static data area to be sure
-	 */
-	static struct diag210 diag210_tmp;
 	static DEFINE_SPINLOCK(diag210_lock);
 	unsigned long flags;
 	int ccode;
 
 	spin_lock_irqsave(&diag210_lock, flags);
-	diag210_tmp = *addr;
+	*__diag210_tmp_dma = *addr;
 
 	diag_stat_inc(DIAG_STAT_X210);
-	asm volatile(
-		"	lhi	%0,-1\n"
-		"	sam31\n"
-		"	diag	%1,0,0x210\n"
-		"0:	ipm	%0\n"
-		"	srl	%0,28\n"
-		"1:	sam64\n"
-		EX_TABLE(0b, 1b)
-		: "=&d" (ccode) : "a" (&diag210_tmp) : "cc", "memory");
-
-	*addr = diag210_tmp;
+	ccode = diag_dma_ops.diag210(__diag210_tmp_dma);
+
+	*addr = *__diag210_tmp_dma;
 	spin_unlock_irqrestore(&diag210_lock, flags);
 
 	return ccode;
@@ -243,27 +214,9 @@ EXPORT_SYMBOL(diag224);
 /*
  * Diagnose 26C: Access Certain System Information
  */
-static inline int __diag26c(void *req, void *resp, enum diag26c_sc subcode)
-{
-	register unsigned long _req asm("2") = (addr_t) req;
-	register unsigned long _resp asm("3") = (addr_t) resp;
-	register unsigned long _subcode asm("4") = subcode;
-	register unsigned long _rc asm("5") = -EOPNOTSUPP;
-
-	asm volatile(
-		"	sam31\n"
-		"	diag	%[rx],%[ry],0x26c\n"
-		"0:	sam64\n"
-		EX_TABLE(0b,0b)
-		: "+d" (_rc)
-		: [rx] "d" (_req), "d" (_resp), [ry] "d" (_subcode)
-		: "cc", "memory");
-	return _rc;
-}
-
 int diag26c(void *req, void *resp, enum diag26c_sc subcode)
 {
 	diag_stat_inc(DIAG_STAT_X26C);
-	return __diag26c(req, resp, subcode);
+	return diag_dma_ops.diag26c(req, resp, subcode);
 }
 EXPORT_SYMBOL(diag26c);
diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index ab09ada0e930..33f704c16bd3 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -139,7 +139,7 @@ static void early_pgm_check_handler(void)
 	unsigned long addr;
 
 	addr = S390_lowcore.program_old_psw.addr;
-	fixup = search_exception_tables(addr);
+	fixup = s390_search_extables(addr);
 	if (!fixup)
 		disabled_wait(0);
 	/* Disable low address protection before storing into lowcore. */
diff --git a/arch/s390/kernel/head64.S b/arch/s390/kernel/head64.S
index 56491e636eab..5aea1a527443 100644
--- a/arch/s390/kernel/head64.S
+++ b/arch/s390/kernel/head64.S
@@ -26,7 +26,6 @@ ENTRY(startup_continue)
 0:	larl	%r1,tod_clock_base
 	mvc	0(16,%r1),__LC_BOOT_CLOCK
 	larl	%r13,.LPG1		# get base
-	lctlg	%c0,%c15,.Lctl-.LPG1(%r13)	# load control registers
 	larl	%r0,boot_vdso_data
 	stg	%r0,__LC_VDSO_PER_CPU
 #
@@ -61,22 +60,6 @@ ENTRY(startup_continue)
 
 	.align	16
 .LPG1:
-.Lctl:	.quad	0x04040000		# cr0: AFP registers & secondary space
-	.quad	0			# cr1: primary space segment table
-	.quad	.Lduct			# cr2: dispatchable unit control table
-	.quad	0			# cr3: instruction authorization
-	.quad	0xffff			# cr4: instruction authorization
-	.quad	.Lduct			# cr5: primary-aste origin
-	.quad	0			# cr6:	I/O interrupts
-	.quad	0			# cr7:	secondary space segment table
-	.quad	0			# cr8:	access registers translation
-	.quad	0			# cr9:	tracing off
-	.quad	0			# cr10: tracing off
-	.quad	0			# cr11: tracing off
-	.quad	0			# cr12: tracing off
-	.quad	0			# cr13: home space segment table
-	.quad	0xc0000000		# cr14: machine check handling off
-	.quad	.Llinkage_stack		# cr15: linkage stack operations
 .Lpcmsk:.quad	0x0000000180000000
 .L4malign:.quad 0xffffffffffc00000
 .Lscan2g:.quad	0x80000000 + 0x20000 - 8	# 2GB + 128K - 8
@@ -84,14 +67,5 @@ ENTRY(startup_continue)
 .Lparmaddr:
 	.quad	PARMAREA
 	.align	64
-.Lduct: .long	0,.Laste,.Laste,0,.Lduald,0,0,0
-	.long	0,0,0,0,0,0,0,0
-.Laste:	.quad	0,0xffffffffffffffff,0,0,0,0,0,0
-	.align	128
-.Lduald:.rept	8
-	.long	0x80000000,0,0,0	# invalid access-list entries
-	.endr
-.Llinkage_stack:
-	.long	0,0,0x89000000,0,0,0,0x8a000000,0
 .Ldw:	.quad	0x0002000180000000,0x0000000000000000
 .Laregs:.long	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index e123c0df83f1..aa8fe768640e 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -1720,7 +1720,7 @@ void s390_reset_system(void)
 
 	/* Disable lowcore protection */
 	__ctl_clear_bit(0, 28);
-	diag308_reset();
+	diag_dma_ops.diag308_reset();
 }
 
 #ifdef CONFIG_KEXEC_FILE
diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index 263426dcf97d..6f1388391620 100644
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -573,7 +573,7 @@ static int kprobe_trap_handler(struct pt_regs *regs, int trapnr)
 		 * In case the user-specified fault handler returned
 		 * zero, try to fix up.
 		 */
-		entry = search_exception_tables(regs->psw.addr);
+		entry = s390_search_extables(regs->psw.addr);
 		if (entry) {
 			regs->psw.addr = extable_fixup(entry);
 			return 1;
diff --git a/arch/s390/kernel/machine_kexec.c b/arch/s390/kernel/machine_kexec.c
index cb582649aba6..4b998d639c32 100644
--- a/arch/s390/kernel/machine_kexec.c
+++ b/arch/s390/kernel/machine_kexec.c
@@ -253,6 +253,8 @@ void arch_crash_save_vmcoreinfo(void)
 	VMCOREINFO_SYMBOL(high_memory);
 	VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS);
 	mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note());
+	vmcoreinfo_append_str("SDMA=%lx\n", __sdma);
+	vmcoreinfo_append_str("EDMA=%lx\n", __edma);
 }
 
 void machine_shutdown(void)
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 94efb1eb34b6..4ccaf5ed96ee 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -101,6 +101,14 @@ unsigned long __bootdata(memory_end);
 unsigned long __bootdata(max_physmem_end);
 struct mem_detect_info __bootdata(mem_detect);
 
+struct exception_table_entry *__bootdata_preserved(__start_dma_ex_table);
+struct exception_table_entry *__bootdata_preserved(__stop_dma_ex_table);
+unsigned long __bootdata_preserved(__swsusp_reset_dma);
+unsigned long __bootdata_preserved(__stext_dma);
+unsigned long __bootdata_preserved(__etext_dma);
+unsigned long __bootdata_preserved(__sdma);
+unsigned long __bootdata_preserved(__edma);
+
 unsigned long VMALLOC_START;
 EXPORT_SYMBOL(VMALLOC_START);
 
@@ -832,6 +840,7 @@ static void __init reserve_kernel(void)
 	memblock_reserve(0, HEAD_END);
 	memblock_reserve((unsigned long)_stext, PFN_PHYS(start_pfn)
 			 - (unsigned long)_stext);
+	memblock_reserve(__sdma, __edma - __sdma);
 }
 
 static void __init setup_memory(void)
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index bd197baf1dc3..88634fb0cc50 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -689,7 +689,7 @@ void __init smp_save_dump_cpus(void)
 			smp_save_cpu_regs(sa, addr, is_boot_cpu, page);
 	}
 	memblock_free(page, PAGE_SIZE);
-	diag308_reset();
+	diag_dma_ops.diag308_reset();
 	pcpu_set_smt(0);
 }
 #endif /* CONFIG_CRASH_DUMP */
diff --git a/arch/s390/kernel/swsusp.S b/arch/s390/kernel/swsusp.S
index 993100c31d65..f5219ce11cc5 100644
--- a/arch/s390/kernel/swsusp.S
+++ b/arch/s390/kernel/swsusp.S
@@ -154,20 +154,13 @@ ENTRY(swsusp_arch_resume)
 	ptlb				/* flush tlb */
 
 	/* Reset System */
-	larl	%r1,restart_entry
-	larl	%r2,.Lrestart_diag308_psw
-	og	%r1,0(%r2)
-	stg	%r1,0(%r0)
 	larl	%r1,.Lnew_pgm_check_psw
 	epsw	%r2,%r3
 	stm	%r2,%r3,0(%r1)
 	mvc	__LC_PGM_NEW_PSW(16,%r0),0(%r1)
-	lghi	%r0,0
-	diag	%r0,%r0,0x308
-restart_entry:
-	lhi	%r1,1
-	sigp	%r1,%r0,SIGP_SET_ARCHITECTURE
-	sam64
+	larl	%r1,__swsusp_reset_dma
+	lg	%r1,0(%r1)
+	BASR_EX	%r14,%r1
 #ifdef CONFIG_SMP
 	larl	%r1,smp_cpu_mt_shift
 	icm	%r1,15,0(%r1)
@@ -275,8 +268,6 @@ restore_registers:
 .Lpanic_string:
 	.asciz	"Resume not possible because suspend CPU is no longer available\n"
 	.align	8
-.Lrestart_diag308_psw:
-	.long	0x00080000,0x80000000
 .Lrestart_suspend_psw:
 	.quad	0x0000000180000000,restart_suspend
 .Lnew_pgm_check_psw:
diff --git a/arch/s390/kernel/traps.c b/arch/s390/kernel/traps.c
index 8003b38c1688..82e81a9f7112 100644
--- a/arch/s390/kernel/traps.c
+++ b/arch/s390/kernel/traps.c
@@ -49,7 +49,7 @@ void do_report_trap(struct pt_regs *regs, int si_signo, int si_code, char *str)
 		report_user_fault(regs, si_signo, 0);
         } else {
                 const struct exception_table_entry *fixup;
-		fixup = search_exception_tables(regs->psw.addr);
+		fixup = s390_search_extables(regs->psw.addr);
                 if (fixup)
 			regs->psw.addr = extable_fixup(fixup);
 		else {
@@ -263,5 +263,6 @@ NOKPROBE_SYMBOL(kernel_stack_overflow);
 
 void __init trap_init(void)
 {
+	sort_extable(__start_dma_ex_table, __stop_dma_ex_table);
 	local_mcck_enable();
 }