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From: Arvind Sankar <nivedita@alum.mit.edu>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arvind Sankar <nivedita@alum.mit.edu>,
	Ard Biesheuvel <ardb@kernel.org>,
	linux-efi <linux-efi@vger.kernel.org>
Subject: Re: [PATCH 0/3] Relocate GOT before calling EFI stub
Date: Tue, 7 Jan 2020 13:08:08 -0500	[thread overview]
Message-ID: <20200107180807.GA1642410@rani.riverdale.lan> (raw)
In-Reply-To: <CAKv+Gu-PU=LqT7MEbSH-0GnJOdakDeaC=ANdmag6JptcfJEJtA@mail.gmail.com>

On Tue, Jan 07, 2020 at 06:59:57PM +0100, Ard Biesheuvel wrote:
> On Tue, 7 Jan 2020 at 18:58, Arvind Sankar <nivedita@alum.mit.edu> wrote:
> >
> > On Tue, Jan 07, 2020 at 03:28:31PM +0100, Ard Biesheuvel wrote:
> > >
> > > Unfortunately, the command line option implements a weaker form of
> > > visibility than the pragma, so it probably comes down to setting the
> > > pragma in a .h file that gets -include'd via the command line so it is
> > > guaranteed to be seen first.
> >
> > Tried hacking that in and it works, tested with gcc 4.6.4.
> 
> Excellent. But in my testing locally, I don't get any GOT entries in
> the first place, strangely enough. So what changes in the output for
> you with visibility hidden compared to before?

Works with 32-bit as well.

Are you checking libstub or boot/compressed? Below is with gcc 4.6 (but
latest binutils). With gcc 9, there's only one left -- trampoline_32bit_src
in pgtable_64.

acpi.o
000000000000025b R_X86_64_REX_GOTPCRELX  boot_params-0x0000000000000004
cmdline.o
00000000000001d3 R_X86_64_REX_GOTPCRELX  boot_params-0x0000000000000004
00000000000001f3 R_X86_64_REX_GOTPCRELX  boot_params-0x0000000000000004
0000000000000223 R_X86_64_REX_GOTPCRELX  boot_params-0x0000000000000004
cpuflags.o
00000000000000a3 R_X86_64_REX_GOTPCRELX  cpu_vendor-0x0000000000000004
00000000000000c5 R_X86_64_REX_GOTPCRELX  cpu-0x0000000000000004
0000000000000127 R_X86_64_REX_GOTPCRELX  cpu-0x0000000000000004
0000000000000144 R_X86_64_REX_GOTPCRELX  cpu-0x0000000000000004
0000000000000153 R_X86_64_REX_GOTPCRELX  cpu-0x0000000000000004
000000000000017b R_X86_64_REX_GOTPCRELX  cpu-0x0000000000000004
early_serial_console.o
000000000000005a R_X86_64_REX_GOTPCRELX  early_serial_base-0x0000000000000004
0000000000000165 R_X86_64_REX_GOTPCRELX  early_serial_base-0x0000000000000004
eboot.o
efi_thunk_64.o
error.o
head_64.o
kaslr_64.o
00000000000001e7 R_X86_64_REX_GOTPCRELX  ptrs_per_p4d-0x0000000000000004
0000000000000372 R_X86_64_REX_GOTPCRELX  __default_kernel_pte_mask-0x0000000000000004
000000000000038b R_X86_64_REX_GOTPCRELX  pgdir_shift-0x0000000000000004
00000000000003ac R_X86_64_REX_GOTPCRELX  __pgtable_l5_enabled-0x0000000000000004
000000000000040a R_X86_64_REX_GOTPCRELX  __pgtable_l5_enabled-0x0000000000000004
00000000000004db R_X86_64_REX_GOTPCRELX  __force_order-0x0000000000000004
00000000000004f2 R_X86_64_REX_GOTPCRELX  __pgtable_l5_enabled-0x0000000000000004
0000000000000517 R_X86_64_REX_GOTPCRELX  _pgtable-0x0000000000000004
00000000000005f3 R_X86_64_REX_GOTPCRELX  __force_order-0x0000000000000004
kaslr.o
0000000000000281 R_X86_64_REX_GOTPCRELX  boot_params-0x0000000000000004
00000000000003e3 R_X86_64_REX_GOTPCRELX  boot_params-0x0000000000000004
0000000000000ba1 R_X86_64_REX_GOTPCRELX  __force_order-0x0000000000000004
0000000000000bb4 R_X86_64_REX_GOTPCRELX  boot_params-0x0000000000000004
0000000000000cc8 R_X86_64_REX_GOTPCRELX  free_mem_ptr-0x0000000000000004
0000000000000cd2 R_X86_64_REX_GOTPCRELX  free_mem_end_ptr-0x0000000000000004
0000000000000d6e R_X86_64_REX_GOTPCRELX  free_mem_ptr-0x0000000000000004
0000000000000f63 R_X86_64_REX_GOTPCRELX  __pgtable_l5_enabled-0x0000000000000004
kernel_info.o
mem_encrypt.o
misc.o
0000000000000015 R_X86_64_REX_GOTPCRELX  free_mem_ptr-0x0000000000000004
000000000000001f R_X86_64_REX_GOTPCRELX  free_mem_end_ptr-0x0000000000000004
0000000000002965 R_X86_64_REX_GOTPCRELX  early_serial_base-0x0000000000000004
0000000000002a43 R_X86_64_REX_GOTPCRELX  boot_params-0x0000000000000004
0000000000002b8e R_X86_64_REX_GOTPCRELX  boot_params-0x0000000000000004
0000000000002bec R_X86_64_REX_GOTPCRELX  boot_params-0x0000000000000004
0000000000002c10 R_X86_64_REX_GOTPCRELX  free_mem_end_ptr-0x0000000000000004
0000000000002c17 R_X86_64_REX_GOTPCRELX  free_mem_ptr-0x0000000000000004
0000000000002d16 R_X86_64_REX_GOTPCRELX  trampoline_32bit-0x0000000000000004
0000000000002f97 R_X86_64_REX_GOTPCRELX  boot_params-0x0000000000000004
0000000000002fea R_X86_64_REX_GOTPCRELX  boot_params-0x0000000000000004
pgtable_64.o
000000000000000d R_X86_64_REX_GOTPCRELX  boot_params-0x0000000000000004
000000000000010a R_X86_64_REX_GOTPCRELX  trampoline_32bit_src-0x0000000000000004
0000000000000191 R_X86_64_REX_GOTPCRELX  __force_order-0x0000000000000004
0000000000000376 R_X86_64_REX_GOTPCRELX  __force_order-0x0000000000000004
piggy.o
string.o

  reply	other threads:[~2020-01-07 18:08 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-07 13:54 [PATCH 0/3] Relocate GOT before calling EFI stub Arvind Sankar
2020-01-07 13:54 ` [PATCH 1/3] x86/boot/compressed/64: Make adjust_got easier to use repeatedly Arvind Sankar
2020-01-07 13:54 ` [PATCH 2/3] x86/boot/compressed/32: Allow adjust_got to be called repeatedly Arvind Sankar
2020-01-07 13:55 ` [PATCH 3/3] x86/boot: Perform GOT relocation before calling EFI stub Arvind Sankar
2020-01-07 14:01 ` [PATCH 0/3] Relocate GOT " Ard Biesheuvel
2020-01-07 14:13   ` Ard Biesheuvel
2020-01-07 14:21     ` Arvind Sankar
2020-01-07 14:24       ` Ard Biesheuvel
2020-01-07 14:27         ` Arvind Sankar
2020-01-07 14:28           ` Ard Biesheuvel
2020-01-07 17:58             ` Arvind Sankar
2020-01-07 17:59               ` Ard Biesheuvel
2020-01-07 18:08                 ` Arvind Sankar [this message]
2020-01-07 18:10                   ` Ard Biesheuvel
2020-01-07 18:32                     ` Arvind Sankar
2020-01-07 19:03                       ` Ard Biesheuvel
2020-01-07 19:14                         ` Arvind Sankar
2020-01-07 19:23                           ` Ard Biesheuvel
2020-01-07 19:51                             ` Ard Biesheuvel
2020-01-07 20:00                               ` Arvind Sankar

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