[PATCH] KVM: arm64: Don't use cbz/adr with external symbols

[PATCH] KVM: arm64: Don't use cbz/adr with external symbols

[Sami Tolvanen]

allmodconfig + CONFIG_LTO_CLANG_THIN=y fails to build due to following
linker errors:

  ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21CC):
  relocation R_AARCH64_CONDBR19 out of range: 2031220 is not in
  [-1048576, 1048575]; references hyp_panic
  >>> defined in vmlinux.o

  ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21E0):
  relocation R_AARCH64_ADR_PREL_LO21 out of range: 2031200 is not in
  [-1048576, 1048575]; references hyp_panic
  >>> defined in vmlinux.o

This is because with LTO, the compiler ends up placing hyp_panic()
more than 1MB away from __guest_enter(). Use an unconditional branch
and adr_l instead to fix the issue.

Link: https://github.com/ClangBuiltLinux/linux/issues/1317
Reported-by: Nathan Chancellor <nathan@kernel.org>
Suggested-by: Marc Zyngier <maz@kernel.org>
Suggested-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
 arch/arm64/kvm/hyp/entry.S | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
index b0afad7a99c6..c62265951467 100644
--- a/arch/arm64/kvm/hyp/entry.S
+++ b/arch/arm64/kvm/hyp/entry.S
@@ -85,8 +85,10 @@ SYM_INNER_LABEL(__guest_exit_panic, SYM_L_GLOBAL)
 
 	// If the hyp context is loaded, go straight to hyp_panic
 	get_loaded_vcpu x0, x1
-	cbz	x0, hyp_panic
+	cbnz	x0, 1f
+	b	hyp_panic
 
+1:
 	// The hyp context is saved so make sure it is restored to allow
 	// hyp_panic to run at hyp and, subsequently, panic to run in the host.
 	// This makes use of __guest_exit to avoid duplication but sets the
@@ -94,7 +96,7 @@ SYM_INNER_LABEL(__guest_exit_panic, SYM_L_GLOBAL)
 	// current state is saved to the guest context but it will only be
 	// accurate if the guest had been completely restored.
 	adr_this_cpu x0, kvm_hyp_ctxt, x1
-	adr	x1, hyp_panic
+	adr_l	x1, hyp_panic
 	str	x1, [x0, #CPU_XREG_OFFSET(30)]
 
 	get_vcpu_ptr	x1, x0

base-commit: 280d542f6ffac0e6d65dc267f92191d509b13b64
-- 
2.30.1.766.gb4fecdf3b7-goog

[PATCH] KVM: arm64: Don't use cbz/adr with external symbols

[Sami Tolvanen]

allmodconfig + CONFIG_LTO_CLANG_THIN=y fails to build due to following
linker errors:

  ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21CC):
  relocation R_AARCH64_CONDBR19 out of range: 2031220 is not in
  [-1048576, 1048575]; references hyp_panic
  >>> defined in vmlinux.o

  ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21E0):
  relocation R_AARCH64_ADR_PREL_LO21 out of range: 2031200 is not in
  [-1048576, 1048575]; references hyp_panic
  >>> defined in vmlinux.o

This is because with LTO, the compiler ends up placing hyp_panic()
more than 1MB away from __guest_enter(). Use an unconditional branch
and adr_l instead to fix the issue.

Link: https://github.com/ClangBuiltLinux/linux/issues/1317
Reported-by: Nathan Chancellor <nathan@kernel.org>
Suggested-by: Marc Zyngier <maz@kernel.org>
Suggested-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
 arch/arm64/kvm/hyp/entry.S | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
index b0afad7a99c6..c62265951467 100644
--- a/arch/arm64/kvm/hyp/entry.S
+++ b/arch/arm64/kvm/hyp/entry.S
@@ -85,8 +85,10 @@ SYM_INNER_LABEL(__guest_exit_panic, SYM_L_GLOBAL)
 
 	// If the hyp context is loaded, go straight to hyp_panic
 	get_loaded_vcpu x0, x1
-	cbz	x0, hyp_panic
+	cbnz	x0, 1f
+	b	hyp_panic
 
+1:
 	// The hyp context is saved so make sure it is restored to allow
 	// hyp_panic to run at hyp and, subsequently, panic to run in the host.
 	// This makes use of __guest_exit to avoid duplication but sets the
@@ -94,7 +96,7 @@ SYM_INNER_LABEL(__guest_exit_panic, SYM_L_GLOBAL)
 	// current state is saved to the guest context but it will only be
 	// accurate if the guest had been completely restored.
 	adr_this_cpu x0, kvm_hyp_ctxt, x1
-	adr	x1, hyp_panic
+	adr_l	x1, hyp_panic
 	str	x1, [x0, #CPU_XREG_OFFSET(30)]
 
 	get_vcpu_ptr	x1, x0

base-commit: 280d542f6ffac0e6d65dc267f92191d509b13b64
-- 
2.30.1.766.gb4fecdf3b7-goog


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH] KVM: arm64: Don't use cbz/adr with external symbols

[Sami Tolvanen]

allmodconfig + CONFIG_LTO_CLANG_THIN=y fails to build due to following
linker errors:

  ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21CC):
  relocation R_AARCH64_CONDBR19 out of range: 2031220 is not in
  [-1048576, 1048575]; references hyp_panic
  >>> defined in vmlinux.o

  ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21E0):
  relocation R_AARCH64_ADR_PREL_LO21 out of range: 2031200 is not in
  [-1048576, 1048575]; references hyp_panic
  >>> defined in vmlinux.o

This is because with LTO, the compiler ends up placing hyp_panic()
more than 1MB away from __guest_enter(). Use an unconditional branch
and adr_l instead to fix the issue.

Link: https://github.com/ClangBuiltLinux/linux/issues/1317
Reported-by: Nathan Chancellor <nathan@kernel.org>
Suggested-by: Marc Zyngier <maz@kernel.org>
Suggested-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
 arch/arm64/kvm/hyp/entry.S | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
index b0afad7a99c6..c62265951467 100644
--- a/arch/arm64/kvm/hyp/entry.S
+++ b/arch/arm64/kvm/hyp/entry.S
@@ -85,8 +85,10 @@ SYM_INNER_LABEL(__guest_exit_panic, SYM_L_GLOBAL)
 
 	// If the hyp context is loaded, go straight to hyp_panic
 	get_loaded_vcpu x0, x1
-	cbz	x0, hyp_panic
+	cbnz	x0, 1f
+	b	hyp_panic
 
+1:
 	// The hyp context is saved so make sure it is restored to allow
 	// hyp_panic to run at hyp and, subsequently, panic to run in the host.
 	// This makes use of __guest_exit to avoid duplication but sets the
@@ -94,7 +96,7 @@ SYM_INNER_LABEL(__guest_exit_panic, SYM_L_GLOBAL)
 	// current state is saved to the guest context but it will only be
 	// accurate if the guest had been completely restored.
 	adr_this_cpu x0, kvm_hyp_ctxt, x1
-	adr	x1, hyp_panic
+	adr_l	x1, hyp_panic
 	str	x1, [x0, #CPU_XREG_OFFSET(30)]
 
 	get_vcpu_ptr	x1, x0

base-commit: 280d542f6ffac0e6d65dc267f92191d509b13b64
-- 
2.30.1.766.gb4fecdf3b7-goog

_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

Re: [PATCH] KVM: arm64: Don't use cbz/adr with external symbols

[Kees Cook]

On Fri, Mar 05, 2021 at 12:21:24PM -0800, Sami Tolvanen wrote:
> allmodconfig + CONFIG_LTO_CLANG_THIN=y fails to build due to following
> linker errors:
> 
>   ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21CC):
>   relocation R_AARCH64_CONDBR19 out of range: 2031220 is not in
>   [-1048576, 1048575]; references hyp_panic
>   >>> defined in vmlinux.o
> 
>   ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21E0):
>   relocation R_AARCH64_ADR_PREL_LO21 out of range: 2031200 is not in
>   [-1048576, 1048575]; references hyp_panic
>   >>> defined in vmlinux.o
> 
> This is because with LTO, the compiler ends up placing hyp_panic()
> more than 1MB away from __guest_enter(). Use an unconditional branch
> and adr_l instead to fix the issue.
> 
> Link: https://github.com/ClangBuiltLinux/linux/issues/1317
> Reported-by: Nathan Chancellor <nathan@kernel.org>
> Suggested-by: Marc Zyngier <maz@kernel.org>
> Suggested-by: Ard Biesheuvel <ardb@kernel.org>
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook

Re: [PATCH] KVM: arm64: Don't use cbz/adr with external symbols

[Kees Cook]

On Fri, Mar 05, 2021 at 12:21:24PM -0800, Sami Tolvanen wrote:
> allmodconfig + CONFIG_LTO_CLANG_THIN=y fails to build due to following
> linker errors:
> 
>   ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21CC):
>   relocation R_AARCH64_CONDBR19 out of range: 2031220 is not in
>   [-1048576, 1048575]; references hyp_panic
>   >>> defined in vmlinux.o
> 
>   ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21E0):
>   relocation R_AARCH64_ADR_PREL_LO21 out of range: 2031200 is not in
>   [-1048576, 1048575]; references hyp_panic
>   >>> defined in vmlinux.o
> 
> This is because with LTO, the compiler ends up placing hyp_panic()
> more than 1MB away from __guest_enter(). Use an unconditional branch
> and adr_l instead to fix the issue.
> 
> Link: https://github.com/ClangBuiltLinux/linux/issues/1317
> Reported-by: Nathan Chancellor <nathan@kernel.org>
> Suggested-by: Marc Zyngier <maz@kernel.org>
> Suggested-by: Ard Biesheuvel <ardb@kernel.org>
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH] KVM: arm64: Don't use cbz/adr with external symbols

[Kees Cook]

On Fri, Mar 05, 2021 at 12:21:24PM -0800, Sami Tolvanen wrote:
> allmodconfig + CONFIG_LTO_CLANG_THIN=y fails to build due to following
> linker errors:
> 
>   ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21CC):
>   relocation R_AARCH64_CONDBR19 out of range: 2031220 is not in
>   [-1048576, 1048575]; references hyp_panic
>   >>> defined in vmlinux.o
> 
>   ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21E0):
>   relocation R_AARCH64_ADR_PREL_LO21 out of range: 2031200 is not in
>   [-1048576, 1048575]; references hyp_panic
>   >>> defined in vmlinux.o
> 
> This is because with LTO, the compiler ends up placing hyp_panic()
> more than 1MB away from __guest_enter(). Use an unconditional branch
> and adr_l instead to fix the issue.
> 
> Link: https://github.com/ClangBuiltLinux/linux/issues/1317
> Reported-by: Nathan Chancellor <nathan@kernel.org>
> Suggested-by: Marc Zyngier <maz@kernel.org>
> Suggested-by: Ard Biesheuvel <ardb@kernel.org>
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook
_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

Re: [PATCH] KVM: arm64: Don't use cbz/adr with external symbols

[Nathan Chancellor]

On Fri, Mar 05, 2021 at 12:21:24PM -0800, Sami Tolvanen wrote:
> allmodconfig + CONFIG_LTO_CLANG_THIN=y fails to build due to following
> linker errors:
> 
>   ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21CC):
>   relocation R_AARCH64_CONDBR19 out of range: 2031220 is not in
>   [-1048576, 1048575]; references hyp_panic
>   >>> defined in vmlinux.o
> 
>   ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21E0):
>   relocation R_AARCH64_ADR_PREL_LO21 out of range: 2031200 is not in
>   [-1048576, 1048575]; references hyp_panic
>   >>> defined in vmlinux.o
> 
> This is because with LTO, the compiler ends up placing hyp_panic()
> more than 1MB away from __guest_enter(). Use an unconditional branch
> and adr_l instead to fix the issue.
> 
> Link: https://github.com/ClangBuiltLinux/linux/issues/1317
> Reported-by: Nathan Chancellor <nathan@kernel.org>
> Suggested-by: Marc Zyngier <maz@kernel.org>
> Suggested-by: Ard Biesheuvel <ardb@kernel.org>
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>

I booted an kernel with this patch in it on my Raspberry Pi 4 and booted
a kernel under KVM without any issues.

Tested-by: Nathan Chancellor <nathan@kernel.org>

> ---
>  arch/arm64/kvm/hyp/entry.S | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
> index b0afad7a99c6..c62265951467 100644
> --- a/arch/arm64/kvm/hyp/entry.S
> +++ b/arch/arm64/kvm/hyp/entry.S
> @@ -85,8 +85,10 @@ SYM_INNER_LABEL(__guest_exit_panic, SYM_L_GLOBAL)
>  
>  	// If the hyp context is loaded, go straight to hyp_panic
>  	get_loaded_vcpu x0, x1
> -	cbz	x0, hyp_panic
> +	cbnz	x0, 1f
> +	b	hyp_panic
>  
> +1:
>  	// The hyp context is saved so make sure it is restored to allow
>  	// hyp_panic to run at hyp and, subsequently, panic to run in the host.
>  	// This makes use of __guest_exit to avoid duplication but sets the
> @@ -94,7 +96,7 @@ SYM_INNER_LABEL(__guest_exit_panic, SYM_L_GLOBAL)
>  	// current state is saved to the guest context but it will only be
>  	// accurate if the guest had been completely restored.
>  	adr_this_cpu x0, kvm_hyp_ctxt, x1
> -	adr	x1, hyp_panic
> +	adr_l	x1, hyp_panic
>  	str	x1, [x0, #CPU_XREG_OFFSET(30)]
>  
>  	get_vcpu_ptr	x1, x0
> 
> base-commit: 280d542f6ffac0e6d65dc267f92191d509b13b64
> -- 
> 2.30.1.766.gb4fecdf3b7-goog
> 
> _______________________________________________
> kvmarm mailing list
> kvmarm@lists.cs.columbia.edu
> https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

Re: [PATCH] KVM: arm64: Don't use cbz/adr with external symbols

[Nathan Chancellor]

On Fri, Mar 05, 2021 at 12:21:24PM -0800, Sami Tolvanen wrote:
> allmodconfig + CONFIG_LTO_CLANG_THIN=y fails to build due to following
> linker errors:
> 
>   ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21CC):
>   relocation R_AARCH64_CONDBR19 out of range: 2031220 is not in
>   [-1048576, 1048575]; references hyp_panic
>   >>> defined in vmlinux.o
> 
>   ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21E0):
>   relocation R_AARCH64_ADR_PREL_LO21 out of range: 2031200 is not in
>   [-1048576, 1048575]; references hyp_panic
>   >>> defined in vmlinux.o
> 
> This is because with LTO, the compiler ends up placing hyp_panic()
> more than 1MB away from __guest_enter(). Use an unconditional branch
> and adr_l instead to fix the issue.
> 
> Link: https://github.com/ClangBuiltLinux/linux/issues/1317
> Reported-by: Nathan Chancellor <nathan@kernel.org>
> Suggested-by: Marc Zyngier <maz@kernel.org>
> Suggested-by: Ard Biesheuvel <ardb@kernel.org>
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>

I booted an kernel with this patch in it on my Raspberry Pi 4 and booted
a kernel under KVM without any issues.

Tested-by: Nathan Chancellor <nathan@kernel.org>

> ---
>  arch/arm64/kvm/hyp/entry.S | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
> index b0afad7a99c6..c62265951467 100644
> --- a/arch/arm64/kvm/hyp/entry.S
> +++ b/arch/arm64/kvm/hyp/entry.S
> @@ -85,8 +85,10 @@ SYM_INNER_LABEL(__guest_exit_panic, SYM_L_GLOBAL)
>  
>  	// If the hyp context is loaded, go straight to hyp_panic
>  	get_loaded_vcpu x0, x1
> -	cbz	x0, hyp_panic
> +	cbnz	x0, 1f
> +	b	hyp_panic
>  
> +1:
>  	// The hyp context is saved so make sure it is restored to allow
>  	// hyp_panic to run at hyp and, subsequently, panic to run in the host.
>  	// This makes use of __guest_exit to avoid duplication but sets the
> @@ -94,7 +96,7 @@ SYM_INNER_LABEL(__guest_exit_panic, SYM_L_GLOBAL)
>  	// current state is saved to the guest context but it will only be
>  	// accurate if the guest had been completely restored.
>  	adr_this_cpu x0, kvm_hyp_ctxt, x1
> -	adr	x1, hyp_panic
> +	adr_l	x1, hyp_panic
>  	str	x1, [x0, #CPU_XREG_OFFSET(30)]
>  
>  	get_vcpu_ptr	x1, x0
> 
> base-commit: 280d542f6ffac0e6d65dc267f92191d509b13b64
> -- 
> 2.30.1.766.gb4fecdf3b7-goog
> 
> _______________________________________________
> kvmarm mailing list
> kvmarm@lists.cs.columbia.edu
> https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH] KVM: arm64: Don't use cbz/adr with external symbols

[Nathan Chancellor]

On Fri, Mar 05, 2021 at 12:21:24PM -0800, Sami Tolvanen wrote:
> allmodconfig + CONFIG_LTO_CLANG_THIN=y fails to build due to following
> linker errors:
> 
>   ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21CC):
>   relocation R_AARCH64_CONDBR19 out of range: 2031220 is not in
>   [-1048576, 1048575]; references hyp_panic
>   >>> defined in vmlinux.o
> 
>   ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21E0):
>   relocation R_AARCH64_ADR_PREL_LO21 out of range: 2031200 is not in
>   [-1048576, 1048575]; references hyp_panic
>   >>> defined in vmlinux.o
> 
> This is because with LTO, the compiler ends up placing hyp_panic()
> more than 1MB away from __guest_enter(). Use an unconditional branch
> and adr_l instead to fix the issue.
> 
> Link: https://github.com/ClangBuiltLinux/linux/issues/1317
> Reported-by: Nathan Chancellor <nathan@kernel.org>
> Suggested-by: Marc Zyngier <maz@kernel.org>
> Suggested-by: Ard Biesheuvel <ardb@kernel.org>
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>

I booted an kernel with this patch in it on my Raspberry Pi 4 and booted
a kernel under KVM without any issues.

Tested-by: Nathan Chancellor <nathan@kernel.org>

> ---
>  arch/arm64/kvm/hyp/entry.S | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
> index b0afad7a99c6..c62265951467 100644
> --- a/arch/arm64/kvm/hyp/entry.S
> +++ b/arch/arm64/kvm/hyp/entry.S
> @@ -85,8 +85,10 @@ SYM_INNER_LABEL(__guest_exit_panic, SYM_L_GLOBAL)
>  
>  	// If the hyp context is loaded, go straight to hyp_panic
>  	get_loaded_vcpu x0, x1
> -	cbz	x0, hyp_panic
> +	cbnz	x0, 1f
> +	b	hyp_panic
>  
> +1:
>  	// The hyp context is saved so make sure it is restored to allow
>  	// hyp_panic to run at hyp and, subsequently, panic to run in the host.
>  	// This makes use of __guest_exit to avoid duplication but sets the
> @@ -94,7 +96,7 @@ SYM_INNER_LABEL(__guest_exit_panic, SYM_L_GLOBAL)
>  	// current state is saved to the guest context but it will only be
>  	// accurate if the guest had been completely restored.
>  	adr_this_cpu x0, kvm_hyp_ctxt, x1
> -	adr	x1, hyp_panic
> +	adr_l	x1, hyp_panic
>  	str	x1, [x0, #CPU_XREG_OFFSET(30)]
>  
>  	get_vcpu_ptr	x1, x0
> 
> base-commit: 280d542f6ffac0e6d65dc267f92191d509b13b64
> -- 
> 2.30.1.766.gb4fecdf3b7-goog
> 
> _______________________________________________
> kvmarm mailing list
> kvmarm@lists.cs.columbia.edu
> https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
_______________________________________________
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Re: [PATCH] KVM: arm64: Don't use cbz/adr with external symbols

[Will Deacon]

On Fri, Mar 05, 2021 at 12:21:24PM -0800, Sami Tolvanen wrote:
> allmodconfig + CONFIG_LTO_CLANG_THIN=y fails to build due to following
> linker errors:
> 
>   ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21CC):
>   relocation R_AARCH64_CONDBR19 out of range: 2031220 is not in
>   [-1048576, 1048575]; references hyp_panic
>   >>> defined in vmlinux.o
> 
>   ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21E0):
>   relocation R_AARCH64_ADR_PREL_LO21 out of range: 2031200 is not in
>   [-1048576, 1048575]; references hyp_panic
>   >>> defined in vmlinux.o
> 
> This is because with LTO, the compiler ends up placing hyp_panic()
> more than 1MB away from __guest_enter(). Use an unconditional branch
> and adr_l instead to fix the issue.
> 
> Link: https://github.com/ClangBuiltLinux/linux/issues/1317
> Reported-by: Nathan Chancellor <nathan@kernel.org>
> Suggested-by: Marc Zyngier <maz@kernel.org>
> Suggested-by: Ard Biesheuvel <ardb@kernel.org>
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
> ---
>  arch/arm64/kvm/hyp/entry.S | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)

Acked-by: Will Deacon <will@kernel.org>

Will

Re: [PATCH] KVM: arm64: Don't use cbz/adr with external symbols

[Will Deacon]

On Fri, Mar 05, 2021 at 12:21:24PM -0800, Sami Tolvanen wrote:
> allmodconfig + CONFIG_LTO_CLANG_THIN=y fails to build due to following
> linker errors:
> 
>   ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21CC):
>   relocation R_AARCH64_CONDBR19 out of range: 2031220 is not in
>   [-1048576, 1048575]; references hyp_panic
>   >>> defined in vmlinux.o
> 
>   ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21E0):
>   relocation R_AARCH64_ADR_PREL_LO21 out of range: 2031200 is not in
>   [-1048576, 1048575]; references hyp_panic
>   >>> defined in vmlinux.o
> 
> This is because with LTO, the compiler ends up placing hyp_panic()
> more than 1MB away from __guest_enter(). Use an unconditional branch
> and adr_l instead to fix the issue.
> 
> Link: https://github.com/ClangBuiltLinux/linux/issues/1317
> Reported-by: Nathan Chancellor <nathan@kernel.org>
> Suggested-by: Marc Zyngier <maz@kernel.org>
> Suggested-by: Ard Biesheuvel <ardb@kernel.org>
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
> ---
>  arch/arm64/kvm/hyp/entry.S | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)

Acked-by: Will Deacon <will@kernel.org>

Will

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Re: [PATCH] KVM: arm64: Don't use cbz/adr with external symbols

[Will Deacon]

On Fri, Mar 05, 2021 at 12:21:24PM -0800, Sami Tolvanen wrote:
> allmodconfig + CONFIG_LTO_CLANG_THIN=y fails to build due to following
> linker errors:
> 
>   ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21CC):
>   relocation R_AARCH64_CONDBR19 out of range: 2031220 is not in
>   [-1048576, 1048575]; references hyp_panic
>   >>> defined in vmlinux.o
> 
>   ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21E0):
>   relocation R_AARCH64_ADR_PREL_LO21 out of range: 2031200 is not in
>   [-1048576, 1048575]; references hyp_panic
>   >>> defined in vmlinux.o
> 
> This is because with LTO, the compiler ends up placing hyp_panic()
> more than 1MB away from __guest_enter(). Use an unconditional branch
> and adr_l instead to fix the issue.
> 
> Link: https://github.com/ClangBuiltLinux/linux/issues/1317
> Reported-by: Nathan Chancellor <nathan@kernel.org>
> Suggested-by: Marc Zyngier <maz@kernel.org>
> Suggested-by: Ard Biesheuvel <ardb@kernel.org>
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
> ---
>  arch/arm64/kvm/hyp/entry.S | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)

Acked-by: Will Deacon <will@kernel.org>

Will
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Re: [PATCH] KVM: arm64: Don't use cbz/adr with external symbols

[Marc Zyngier]

On Fri, 5 Mar 2021 12:21:24 -0800, Sami Tolvanen wrote:
> allmodconfig + CONFIG_LTO_CLANG_THIN=y fails to build due to following
> linker errors:
> 
>   ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21CC):
>   relocation R_AARCH64_CONDBR19 out of range: 2031220 is not in
>   [-1048576, 1048575]; references hyp_panic
>   >>> defined in vmlinux.o
> 
> [...]

Applied to next, thanks!

[1/1] KVM: arm64: Don't use cbz/adr with external symbols
      commit: dbaee836d60a8e1b03e7d53a37893235662ba124

Cheers,

	M.
-- 
Without deviation from the norm, progress is not possible.

Re: [PATCH] KVM: arm64: Don't use cbz/adr with external symbols

[Marc Zyngier]

On Fri, 5 Mar 2021 12:21:24 -0800, Sami Tolvanen wrote:
> allmodconfig + CONFIG_LTO_CLANG_THIN=y fails to build due to following
> linker errors:
> 
>   ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21CC):
>   relocation R_AARCH64_CONDBR19 out of range: 2031220 is not in
>   [-1048576, 1048575]; references hyp_panic
>   >>> defined in vmlinux.o
> 
> [...]

Applied to next, thanks!

[1/1] KVM: arm64: Don't use cbz/adr with external symbols
      commit: dbaee836d60a8e1b03e7d53a37893235662ba124

Cheers,

	M.
-- 
Without deviation from the norm, progress is not possible.



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Re: [PATCH] KVM: arm64: Don't use cbz/adr with external symbols

[Marc Zyngier]

On Fri, 5 Mar 2021 12:21:24 -0800, Sami Tolvanen wrote:
> allmodconfig + CONFIG_LTO_CLANG_THIN=y fails to build due to following
> linker errors:
> 
>   ld.lld: error: irqbypass.c:(function __guest_enter: .text+0x21CC):
>   relocation R_AARCH64_CONDBR19 out of range: 2031220 is not in
>   [-1048576, 1048575]; references hyp_panic
>   >>> defined in vmlinux.o
> 
> [...]

Applied to next, thanks!

[1/1] KVM: arm64: Don't use cbz/adr with external symbols
      commit: dbaee836d60a8e1b03e7d53a37893235662ba124

Cheers,

	M.
-- 
Without deviation from the norm, progress is not possible.


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