s390/boot: do not change default_lma

The current modification of the default_lma is illogical and should be
avoided. It would be more appropriate to introduce and utilize a new
variable vmlinux_lma instead, so that default_lma remains unchanged and
at its original "default" value of 0x100000.

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

diff --git a/arch/s390/boot/startup.c b/arch/s390/boot/startup.c
index cc0ca7e..e1edb61 100644 (file)
--- a/arch/s390/boot/startup.c
+++ b/arch/s390/boot/startup.c
@@ -235,9 +235,9 @@ static unsigned long setup_kernel_memory_layout(void)
 /*
  * This function clears the BSS section of the decompressed Linux kernel and NOT the decompressor's.
  */
-static void clear_bss_section(void)
+static void clear_bss_section(unsigned long vmlinux_lma)
 {
-       memset((void *)vmlinux.default_lma + vmlinux.image_size, 0, vmlinux.bss_size);
+       memset((void *)vmlinux_lma + vmlinux.image_size, 0, vmlinux.bss_size);
 }
 
 /*
@@ -256,7 +256,6 @@ static void setup_vmalloc_size(void)
 
 static void offset_vmlinux_info(unsigned long offset)
 {
-       vmlinux.default_lma += offset;
        *(unsigned long *)(&vmlinux.entry) += offset;
        vmlinux.bootdata_off += offset;
        vmlinux.bootdata_preserved_off += offset;
@@ -278,7 +277,7 @@ static void offset_vmlinux_info(unsigned long offset)
 void startup_kernel(void)
 {
        unsigned long max_physmem_end;
-       unsigned long random_lma;
+       unsigned long vmlinux_lma = 0;
        unsigned long asce_limit;
        unsigned long safe_addr;
        void *img;
@@ -316,26 +315,26 @@ void startup_kernel(void)
        rescue_initrd(safe_addr, ident_map_size);
 
        if (kaslr_enabled()) {
-               random_lma = get_random_base();
-               if (random_lma) {
-                       __kaslr_offset = random_lma - vmlinux.default_lma;
-                       img = (void *)vmlinux.default_lma;
+               vmlinux_lma = get_random_base();
+               if (vmlinux_lma) {
+                       __kaslr_offset = vmlinux_lma - vmlinux.default_lma;
                        offset_vmlinux_info(__kaslr_offset);
                }
        }
+       vmlinux_lma = vmlinux_lma ?: vmlinux.default_lma;
+       physmem_reserve(RR_VMLINUX, vmlinux_lma, vmlinux.image_size + vmlinux.bss_size);
 
        if (!IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED)) {
                img = decompress_kernel();
-               memmove((void *)vmlinux.default_lma, img, vmlinux.image_size);
+               memmove((void *)vmlinux_lma, img, vmlinux.image_size);
        } else if (__kaslr_offset) {
-               memcpy((void *)vmlinux.default_lma, img, vmlinux.image_size);
+               img = (void *)vmlinux.default_lma;
+               memmove((void *)vmlinux_lma, img, vmlinux.image_size);
                memset(img, 0, vmlinux.image_size);
        }
 
        /* vmlinux decompression is done, shrink reserved low memory */
        physmem_reserve(RR_DECOMPRESSOR, 0, (unsigned long)_decompressor_end);
-       if (!__kaslr_offset)
-               physmem_reserve(RR_VMLINUX, vmlinux.default_lma, vmlinux.image_size + vmlinux.bss_size);
        physmem_alloc_range(RR_AMODE31, vmlinux.amode31_size, PAGE_SIZE, 0, SZ_2G, true);
 
        /*
@@ -351,7 +350,7 @@ void startup_kernel(void)
         * - copy_bootdata() must follow setup_vmem() to propagate changes to
         *   bootdata made by setup_vmem()
         */
-       clear_bss_section();
+       clear_bss_section(vmlinux_lma);
        handle_relocs(__kaslr_offset);
        setup_vmem(asce_limit);
        copy_bootdata();