[PATCH] i386/relocator_common.S: drop empty #ifdef
Signed-off-by: Cao jin --- grub-core/lib/i386/relocator_common.S | 2 -- 1 file changed, 2 deletions(-) diff --git a/grub-core/lib/i386/relocator_common.S b/grub-core/lib/i386/relocator_common.S index 03f427a03..1b5210dd3 100644 --- a/grub-core/lib/i386/relocator_common.S +++ b/grub-core/lib/i386/relocator_common.S @@ -29,8 +29,6 @@ #endif .macro DISABLE_PAGING -#ifdef GRUB_MACHINE_IEEE1275 -#endif movl%cr0, %eax andl$(~GRUB_MEMORY_CPU_CR0_PAGING_ON), %eax -- 2.21.1 ___ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
[PATCH] realmode.S: update comments
Commit b81d609e4c forget to update it. Signed-off-by: Cao jin --- grub-core/kern/i386/realmode.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/grub-core/kern/i386/realmode.S b/grub-core/kern/i386/realmode.S index 998fdc756..265cdcb9d 100644 --- a/grub-core/kern/i386/realmode.S +++ b/grub-core/kern/i386/realmode.S @@ -77,7 +77,7 @@ protstack: * description. */ - .p2align5 /* force 4-byte alignment */ + .p2align5 /* force 32-byte alignment */ gdt: .word 0, 0 .byte 0, 0, 0, 0 -- 2.21.1 ___ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
Re: questions about relocator16.S
Sorry I don't see reply in time because I am not on the TO or CC list. On 08/14/2018 04:36 PM, Vladimir 'phcoder' Serbinenko wrote: > > > вт, 14 авг. 2018 г., 9:11 Cao jin <mailto:caoj.f...@cn.fujitsu.com>>: > > Hi, > > I am learning these code, and now have 2 questions: > > 1. at the bottom of relocator_common.S, there is: > > LOCAL(jump_vector): > /* Jump location. Is filled by the code */ > .long 0 > .long CODE_SEGMENT > > Since it is offset & segment selector value, why is not ".word > CODE_SEGMENT", is there any subtle difference? > > i386 is little endian, so effectively it just reserves 2 bytes more and > fills them with zeros. > Yes, I think so. > > 2. in relocator16.S, after "RELOAD_GDT", the other segment registers are > updated two times with DATA_SEGMENT & PSEUDO_REAL_DSEG, they are pretty > close, there is no memory read/write between them, so why we need the > updates with DATA_SEGMENT? > > It's derived from older code that may have had accesses there. But it > was tested on many CPUs and changing it risks triggering obscure bug in > an obscure CPU > I see. Thanks very much for your explanation, Vladimir:) -- Sincerely, Cao jin ___ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
questions about relocator16.S
Hi, I am learning these code, and now have 2 questions: 1. at the bottom of relocator_common.S, there is: LOCAL(jump_vector): /* Jump location. Is filled by the code */ .long 0 .long CODE_SEGMENT Since it is offset & segment selector value, why is not ".word CODE_SEGMENT", is there any subtle difference? 2. in relocator16.S, after "RELOAD_GDT", the other segment registers are updated two times with DATA_SEGMENT & PSEUDO_REAL_DSEG, they are pretty close, there is no memory read/write between them, so why we need the updates with DATA_SEGMENT? -- Sincerely, Cao jin ___ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
[PATCH] relocator16.S: comments update
Signed-off-by: Cao jin --- grub-core/lib/i386/relocator16.S | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/grub-core/lib/i386/relocator16.S b/grub-core/lib/i386/relocator16.S index c8d6f86d8..a8b48d2c4 100644 --- a/grub-core/lib/i386/relocator16.S +++ b/grub-core/lib/i386/relocator16.S @@ -204,8 +204,8 @@ LOCAL(gate_a20_check_state): ret LOCAL(gate_a20_done): - /* we are in real mode now -* set up the real mode segment registers : DS, SS, ES + /* we are in real mode now. Set up the real mode segment registers and +* all the other general purpose registers. cs is updated with ljmp. */ /* movw imm16, %ax. */ .byte 0xb8 @@ -298,7 +298,7 @@ LOCAL(gdt): .byte 0, 0x92, 0xCF, 0 /* -- 16 bit real mode CS -- -* base = 0x, limit 0x0 (1 B Granularity), present +* base = filled by code, limit 0x0 (1 B Granularity), present * type = 16 bit code execute/read only/conforming, DPL = 0 */ .word 0x -- 2.17.0 ___ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
[PATCH] linux16 module: code cleanup
1. move relocator related code more close to each other
2. use variable "len" since it has correct assignment, and keep coding
style with upper code
Signed-off-by: Cao jin
---
grub-core/loader/i386/pc/linux.c | 11 +--
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/grub-core/loader/i386/pc/linux.c b/grub-core/loader/i386/pc/linux.c
index b69cb7a3a..531b58d37 100644
--- a/grub-core/loader/i386/pc/linux.c
+++ b/grub-core/loader/i386/pc/linux.c
@@ -236,10 +236,6 @@ grub_cmd_linux (grub_command_t cmd __attribute__
((unused)),
(unsigned) real_size,
(unsigned) grub_linux16_prot_size);
- relocator = grub_relocator_new ();
- if (!relocator)
-goto fail;
-
for (i = 1; i < argc; i++)
if (grub_memcmp (argv[i], "vga=", 4) == 0)
{
@@ -299,6 +295,10 @@ grub_cmd_linux (grub_command_t cmd __attribute__
((unused)),
}
}
+ relocator = grub_relocator_new ();
+ if (!relocator)
+goto fail;
+
{
grub_relocator_chunk_t ch;
err = grub_relocator_alloc_chunk_addr (relocator, &ch,
@@ -355,8 +355,7 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
}
len = grub_linux16_prot_size;
- if (grub_file_read (file, grub_linux_prot_chunk, grub_linux16_prot_size)
- != (grub_ssize_t) grub_linux16_prot_size && !grub_errno)
+ if (grub_file_read (file, grub_linux_prot_chunk, len) != len && !grub_errno)
grub_error (GRUB_ERR_BAD_OS, N_("premature end of file %s"),
argv[0]);
--
2.17.0
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[PATCH] grub-setup: debug message cleanup
variable "root" is initialized after root device probing, and is null in
current place, so, drop it.
Signed-off-by: Cao jin
---
util/setup.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
BTW, I am still not very sure about "root device" in grub, is it the
partition where boot directory resides?
diff --git a/util/setup.c b/util/setup.c
index 8aa5a39a7..7d3bf2c27 100644
--- a/util/setup.c
+++ b/util/setup.c
@@ -298,9 +298,8 @@ SETUP (const char *dir,
bl.first_block = (struct grub_boot_blocklist *) (core_img
+ GRUB_DISK_SECTOR_SIZE
- sizeof (*bl.block));
- grub_util_info ("root is `%s', dest is `%s'", root, dest);
- grub_util_info ("Opening dest");
+ grub_util_info ("Opening dest `%s'", dest);
dest_dev = grub_device_open (dest);
if (! dest_dev)
grub_util_error ("%s", grub_errmsg);
--
2.14.3
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[PATCH] diskboot: trivial correction on stale comments
diskboot.img now is loaded at 0x8000 and is jumped to with 0:0x8000. Signed-off-by: Cao jin --- grub-core/boot/i386/pc/diskboot.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/grub-core/boot/i386/pc/diskboot.S b/grub-core/boot/i386/pc/diskboot.S index 1ee4cf5b2..c1addc0df 100644 --- a/grub-core/boot/i386/pc/diskboot.S +++ b/grub-core/boot/i386/pc/diskboot.S @@ -37,8 +37,8 @@ start: _start: /* -* _start is loaded at 0x2000 and is jumped to with -* CS:IP 0:0x2000 in kernel. +* _start is loaded at 0x8000 and is jumped to with +* CS:IP 0:0x8000 in kernel. */ /* -- 2.14.3 ___ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
Re: stale comment in diskboot.S ?
Hi Daniel, On 04/11/2018 04:25 AM, Daniel Kiper wrote: > On Wed, Mar 28, 2018 at 04:09:00PM +0800, Cao jin wrote: >> Hi, >> >> I was reading the code, and I want to confirm is following comment is stale? >> >> /* >> * _start is loaded at 0x2000 and is jumped to with >> * CS:IP 0:0x2000 in kernel. >> */ >> >> As I understand, it is loaded at 0x8000 and is jumped to with 0:0x8000. > > It looks that you are right. Could you fix that comment? > I am happy to take a patch for it. > Sure, patch is on the way. -- Sincerely, Cao jin ___ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
stale comment in diskboot.S ?
Hi, I was reading the code, and I want to confirm is following comment is stale? /* * _start is loaded at 0x2000 and is jumped to with * CS:IP 0:0x2000 in kernel. */ As I understand, it is loaded at 0x8000 and is jumped to with 0:0x8000. -- Sincerely, Cao jin ___ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
