s390/ipl: read IPL report at early boot

Read the IPL Report block provided by secure-boot, add the entries
of the certificate list to the system key ring and print the list
of components.

PR: Adjust to Vasilys bootdata_preserved patch set. Preserve ipl_cert_list
for later use in kexec_file.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Philipp Rudo <prudo@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/boot/Makefile

@@ -28,8 +28,9 @@ endif
 
 CFLAGS_sclp_early_core.o += -I$(srctree)/drivers/s390/char
 
-obj-y	:= head.o als.o startup.o mem_detect.o ipl_parm.o string.o ebcdic.o
-obj-y	+= sclp_early_core.o mem.o ipl_vmparm.o cmdline.o ctype.o
+obj-y	:= head.o als.o startup.o mem_detect.o ipl_parm.o ipl_report.o
+obj-y	+= string.o ebcdic.o sclp_early_core.o mem.o ipl_vmparm.o cmdline.o
+obj-y	+= ctype.o
 obj-$(CONFIG_PROTECTED_VIRTUALIZATION_GUEST)	+= uv.o
 targets	:= bzImage startup.a section_cmp.boot.data section_cmp.boot.preserved.data $(obj-y)
 subdir-	:= compressed

arch/s390/boot/boot.h

@@ -10,4 +10,6 @@ void parse_boot_command_line(void);
 void setup_memory_end(void);
 void print_missing_facilities(void);
 
+unsigned long read_ipl_report(unsigned long safe_offset);
+
 #endif /* BOOT_BOOT_H */

arch/s390/boot/ipl_report.c

@@ -0,0 +1,165 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/init.h>
+#include <linux/ctype.h>
+#include <asm/ebcdic.h>
+#include <asm/sclp.h>
+#include <asm/sections.h>
+#include <asm/boot_data.h>
+#include <uapi/asm/ipl.h>
+#include "boot.h"
+
+int __bootdata_preserved(ipl_secure_flag);
+
+unsigned long __bootdata_preserved(ipl_cert_list_addr);
+unsigned long __bootdata_preserved(ipl_cert_list_size);
+
+unsigned long __bootdata(early_ipl_comp_list_addr);
+unsigned long __bootdata(early_ipl_comp_list_size);
+
+#define for_each_rb_entry(entry, rb) \
+	for (entry = rb->entries; \
+	     (void *) entry + sizeof(*entry) <= (void *) rb + rb->len; \
+	     entry++)
+
+static inline bool intersects(unsigned long addr0, unsigned long size0,
+			      unsigned long addr1, unsigned long size1)
+{
+	return addr0 + size0 > addr1 && addr1 + size1 > addr0;
+}
+
+static unsigned long find_bootdata_space(struct ipl_rb_components *comps,
+					 struct ipl_rb_certificates *certs,
+					 unsigned long safe_addr)
+{
+	struct ipl_rb_certificate_entry *cert;
+	struct ipl_rb_component_entry *comp;
+	size_t size;
+
+	/*
+	 * Find the length for the IPL report boot data
+	 */
+	early_ipl_comp_list_size = 0;
+	for_each_rb_entry(comp, comps)
+		early_ipl_comp_list_size += sizeof(*comp);
+	ipl_cert_list_size = 0;
+	for_each_rb_entry(cert, certs)
+		ipl_cert_list_size += sizeof(unsigned int) + cert->len;
+	size = ipl_cert_list_size + early_ipl_comp_list_size;
+
+	/*
+	 * Start from safe_addr to find a free memory area large
+	 * enough for the IPL report boot data. This area is used
+	 * for ipl_cert_list_addr/ipl_cert_list_size and
+	 * early_ipl_comp_list_addr/early_ipl_comp_list_size. It must
+	 * not overlap with any component or any certificate.
+	 */
+repeat:
+	if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && INITRD_START && INITRD_SIZE &&
+	    intersects(INITRD_START, INITRD_SIZE, safe_addr, size))
+		safe_addr = INITRD_START + INITRD_SIZE;
+	for_each_rb_entry(comp, comps)
+		if (intersects(safe_addr, size, comp->addr, comp->len)) {
+			safe_addr = comp->addr + comp->len;
+			goto repeat;
+		}
+	for_each_rb_entry(cert, certs)
+		if (intersects(safe_addr, size, cert->addr, cert->len)) {
+			safe_addr = cert->addr + cert->len;
+			goto repeat;
+		}
+	early_ipl_comp_list_addr = safe_addr;
+	ipl_cert_list_addr = safe_addr + early_ipl_comp_list_size;
+
+	return safe_addr + size;
+}
+
+static void copy_components_bootdata(struct ipl_rb_components *comps)
+{
+	struct ipl_rb_component_entry *comp, *ptr;
+
+	ptr = (struct ipl_rb_component_entry *) early_ipl_comp_list_addr;
+	for_each_rb_entry(comp, comps)
+		memcpy(ptr++, comp, sizeof(*ptr));
+}
+
+static void copy_certificates_bootdata(struct ipl_rb_certificates *certs)
+{
+	struct ipl_rb_certificate_entry *cert;
+	void *ptr;
+
+	ptr = (void *) ipl_cert_list_addr;
+	for_each_rb_entry(cert, certs) {
+		*(unsigned int *) ptr = cert->len;
+		ptr += sizeof(unsigned int);
+		memcpy(ptr, (void *) cert->addr, cert->len);
+		ptr += cert->len;
+	}
+}
+
+unsigned long read_ipl_report(unsigned long safe_addr)
+{
+	struct ipl_rb_certificates *certs;
+	struct ipl_rb_components *comps;
+	struct ipl_pl_hdr *pl_hdr;
+	struct ipl_rl_hdr *rl_hdr;
+	struct ipl_rb_hdr *rb_hdr;
+	unsigned long tmp;
+	void *rl_end;
+
+	/*
+	 * Check if there is a IPL report by looking at the copy
+	 * of the IPL parameter information block.
+	 */
+	if (!ipl_block_valid ||
+	    !(ipl_block.hdr.flags & IPL_PL_FLAG_IPLSR))
+		return safe_addr;
+	ipl_secure_flag = !!(ipl_block.hdr.flags & IPL_PL_FLAG_SIPL);
+	/*
+	 * There is an IPL report, to find it load the pointer to the
+	 * IPL parameter information block from lowcore and skip past
+	 * the IPL parameter list, then align the address to a double
+	 * word boundary.
+	 */
+	tmp = (unsigned long) S390_lowcore.ipl_parmblock_ptr;
+	pl_hdr = (struct ipl_pl_hdr *) tmp;
+	tmp = (tmp + pl_hdr->len + 7) & -8UL;
+	rl_hdr = (struct ipl_rl_hdr *) tmp;
+	/* Walk through the IPL report blocks in the IPL Report list */
+	certs = NULL;
+	comps = NULL;
+	rl_end = (void *) rl_hdr + rl_hdr->len;
+	rb_hdr = (void *) rl_hdr + sizeof(*rl_hdr);
+	while ((void *) rb_hdr + sizeof(*rb_hdr) < rl_end &&
+	       (void *) rb_hdr + rb_hdr->len <= rl_end) {
+
+		switch (rb_hdr->rbt) {
+		case IPL_RBT_CERTIFICATES:
+			certs = (struct ipl_rb_certificates *) rb_hdr;
+			break;
+		case IPL_RBT_COMPONENTS:
+			comps = (struct ipl_rb_components *) rb_hdr;
+			break;
+		default:
+			break;
+		}
+
+		rb_hdr = (void *) rb_hdr + rb_hdr->len;
+	}
+
+	/*
+	 * With either the component list or the certificate list
+	 * missing the kernel will stay ignorant of secure IPL.
+	 */
+	if (!comps || !certs)
+		return safe_addr;
+
+	/*
+	 * Copy component and certificate list to a safe area
+	 * where the decompressed kernel can find them.
+	 */
+	safe_addr = find_bootdata_space(comps, certs, safe_addr);
+	copy_components_bootdata(comps);
+	copy_certificates_bootdata(certs);
+
+	return safe_addr;
+}

arch/s390/boot/startup.c

@@ -25,19 +25,16 @@ unsigned long mem_safe_offset(void)
 }
 #endif
 
-static void rescue_initrd(void)
+static void rescue_initrd(unsigned long addr)
 {
-	unsigned long min_initrd_addr;
-
 	if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD))
 		return;
 	if (!INITRD_START || !INITRD_SIZE)
 		return;
-	min_initrd_addr = mem_safe_offset();
-	if (min_initrd_addr <= INITRD_START)
+	if (addr <= INITRD_START)
 		return;
-	memmove((void *)min_initrd_addr, (void *)INITRD_START, INITRD_SIZE);
-	INITRD_START = min_initrd_addr;
+	memmove((void *)addr, (void *)INITRD_START, INITRD_SIZE);
+	INITRD_START = addr;
 }
 
 static void copy_bootdata(void)
@@ -52,12 +49,15 @@ static void copy_bootdata(void)
 
 void startup_kernel(void)
 {
+	unsigned long safe_addr;
 	void *img;
 
-	uv_query_info();
-	rescue_initrd();
-	sclp_early_read_info();
 	store_ipl_parmblock();
+	safe_addr = mem_safe_offset();
+	safe_addr = read_ipl_report(safe_addr);
+	uv_query_info();
+	rescue_initrd(safe_addr);
+	sclp_early_read_info();
 	setup_boot_command_line();
 	parse_boot_command_line();
 	setup_memory_end();