Re: [PATCH v2 1/1] xen/arm64: entry: Add missing code symbol annotations

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Tue, 16 Apr 2024, Edgar E. Iglesias wrote:
> From: "Edgar E. Iglesias" <edgar.iglesias@xxxxxxx>
> 
> Use the generic xen/linkage.h macros when and add missing
                                        ^ when what?

> code symbol annotations.
> 
> Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xxxxxxx>

I am looking at the implementation of FUNC and as far as I can tell
there is no change compared to ENTRY. So from that point of view we are
good. I wonder if we should keep using "ENTRY" because it is nice to
mark explicitely the entry points as such but at the same time I am also
OK with this. I'll let the other ARM maintainers decide.

On the other hand, FUNC_LOCAL does introduce a change: it adds a .align
everywhere. Should not be harmful?

With the commit message fixed:

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
>  xen/arch/arm/arm64/entry.S | 72 +++++++++++++++++++++++++-------------
>  1 file changed, 48 insertions(+), 24 deletions(-)
> 
> diff --git a/xen/arch/arm/arm64/entry.S b/xen/arch/arm/arm64/entry.S
> index f963c923bb..af9a592cae 100644
> --- a/xen/arch/arm/arm64/entry.S
> +++ b/xen/arch/arm/arm64/entry.S
> @@ -289,21 +289,25 @@
>          b       do_bad_mode
>          .endm
>  
> -hyp_sync_invalid:
> +FUNC_LOCAL(hyp_sync_invalid)
>          entry   hyp=1
>          invalid BAD_SYNC
> +END(hyp_sync_invalid)
>  
> -hyp_irq_invalid:
> +FUNC_LOCAL(hyp_irq_invalid)
>          entry   hyp=1
>          invalid BAD_IRQ
> +END(hyp_irq_invalid)
>  
> -hyp_fiq_invalid:
> +FUNC_LOCAL(hyp_fiq_invalid)
>          entry   hyp=1
>          invalid BAD_FIQ
> +END(hyp_fiq_invalid)
>  
> -hyp_error_invalid:
> +FUNC_LOCAL(hyp_error_invalid)
>          entry   hyp=1
>          invalid BAD_ERROR
> +END(hyp_error_invalid)
>  
>  /*
>   * SError received while running in the hypervisor mode.
> @@ -313,11 +317,12 @@ hyp_error_invalid:
>   * simplicity, as SError should be rare and potentially fatal,
>   * all interrupts are kept masked.
>   */
> -hyp_error:
> +FUNC_LOCAL(hyp_error)
>          entry   hyp=1
>          mov     x0, sp
>          bl      do_trap_hyp_serror
>          exit    hyp=1
> +END(hyp_error)
>  
>  /*
>   * Synchronous exception received while running in the hypervisor mode.
> @@ -327,7 +332,7 @@ hyp_error:
>   * some of them. So we want to inherit the state from the interrupted
>   * context.
>   */
> -hyp_sync:
> +FUNC_LOCAL(hyp_sync)
>          entry   hyp=1
>  
>          /* Inherit interrupts */
> @@ -338,6 +343,7 @@ hyp_sync:
>          mov     x0, sp
>          bl      do_trap_hyp_sync
>          exit    hyp=1
> +END(hyp_sync)
>  
>  /*
>   * IRQ received while running in the hypervisor mode.
> @@ -352,7 +358,7 @@ hyp_sync:
>   * would require some rework in some paths (e.g. panic, livepatch) to
>   * ensure the ordering is enforced everywhere.
>   */
> -hyp_irq:
> +FUNC_LOCAL(hyp_irq)
>          entry   hyp=1
>  
>          /* Inherit D, A, F interrupts and keep I masked */
> @@ -365,8 +371,9 @@ hyp_irq:
>          mov     x0, sp
>          bl      do_trap_irq
>          exit    hyp=1
> +END(hyp_irq)
>  
> -guest_sync:
> +FUNC_LOCAL(guest_sync)
>          /*
>           * Save x0, x1 in advance
>           */
> @@ -413,8 +420,9 @@ fastpath_out_workaround:
>          mov     x1, xzr
>          eret
>          sb
> +END(guest_sync)
>  
> -wa2_ssbd:
> +FUNC_LOCAL(wa2_ssbd)
>  #ifdef CONFIG_ARM_SSBD
>  alternative_cb arm_enable_wa2_handling
>          b       wa2_end
> @@ -450,42 +458,55 @@ wa2_end:
>          mov     x0, xzr
>          eret
>          sb
> -guest_sync_slowpath:
> +END(wa2_ssbd)
> +
> +FUNC_LOCAL(guest_sync_slowpath)
>          /*
>           * x0/x1 may have been scratch by the fast path above, so avoid
>           * to save them.
>           */
>          guest_vector compat=0, iflags=IFLAGS__AI_, trap=guest_sync, 
> save_x0_x1=0
> +END(guest_sync_slowpath)
>  
> -guest_irq:
> +FUNC_LOCAL(guest_irq)
>          guest_vector compat=0, iflags=IFLAGS__A__, trap=irq
> +END(guest_irq)
>  
> -guest_fiq_invalid:
> +FUNC_LOCAL(guest_fiq_invalid)
>          entry   hyp=0, compat=0
>          invalid BAD_FIQ
> +END(guest_fiq_invalid)
>  
> -guest_error:
> +FUNC_LOCAL(guest_error)
>          guest_vector compat=0, iflags=IFLAGS__AI_, trap=guest_serror
> +END(guest_error)
>  
> -guest_sync_compat:
> +FUNC_LOCAL(guest_sync_compat)
>          guest_vector compat=1, iflags=IFLAGS__AI_, trap=guest_sync
> +END(guest_sync_compat)
>  
> -guest_irq_compat:
> +FUNC_LOCAL(guest_irq_compat)
>          guest_vector compat=1, iflags=IFLAGS__A__, trap=irq
> +END(guest_irq_compat)
>  
> -guest_fiq_invalid_compat:
> +FUNC_LOCAL(guest_fiq_invalid_compat)
>          entry   hyp=0, compat=1
>          invalid BAD_FIQ
> +END(guest_fiq_invalid_compat)
>  
> -guest_error_compat:
> +FUNC_LOCAL(guest_error_compat)
>          guest_vector compat=1, iflags=IFLAGS__AI_, trap=guest_serror
> +END(guest_error_compat)
>  
> -ENTRY(return_to_new_vcpu32)
> +FUNC(return_to_new_vcpu32)
>          exit    hyp=0, compat=1
> -ENTRY(return_to_new_vcpu64)
> +END(return_to_new_vcpu32)
> +
> +FUNC(return_to_new_vcpu64)
>          exit    hyp=0, compat=0
> +END(return_to_new_vcpu64)
>  
> -return_from_trap:
> +FUNC_LOCAL(return_from_trap)
>          msr     daifset, #IFLAGS___I_ /* Mask interrupts */
>  
>          ldr     x21, [sp, #UREGS_PC]            /* load ELR */
> @@ -524,6 +545,7 @@ return_from_trap:
>  
>          eret
>          sb
> +END(return_from_trap)
>  
>  /*
>   * Consume pending SError generated by the guest if any.
> @@ -536,7 +558,7 @@ return_from_trap:
>   * it. So the function will unmask SError exception for a small window and
>   * then mask it again.
>   */
> -check_pending_guest_serror:
> +FUNC_LOCAL(check_pending_guest_serror)
>          /*
>           * Save elr_el2 to check whether the pending SError exception takes
>           * place while we are doing this sync exception.
> @@ -586,7 +608,7 @@ abort_guest_exit_end:
>          cset    x19, ne
>  
>          ret
> -ENDPROC(check_pending_guest_serror)
> +END(check_pending_guest_serror)
>  
>  /*
>   * Exception vectors.
> @@ -597,7 +619,7 @@ ENDPROC(check_pending_guest_serror)
>          .endm
>  
>          .align  11
> -ENTRY(hyp_traps_vector)
> +FUNC(hyp_traps_vector)
>          ventry  hyp_sync_invalid            /* Synchronous EL2t */
>          ventry  hyp_irq_invalid             /* IRQ EL2t */
>          ventry  hyp_fiq_invalid             /* FIQ EL2t */
> @@ -617,6 +639,7 @@ ENTRY(hyp_traps_vector)
>          ventry  guest_irq_compat            /* IRQ 32-bit EL0/EL1 */
>          ventry  guest_fiq_invalid_compat    /* FIQ 32-bit EL0/EL1 */
>          ventry  guest_error_compat          /* Error 32-bit EL0/EL1 */
> +END(hyp_traps_vector)
>  
>  /*
>   * struct vcpu *__context_switch(struct vcpu *prev, struct vcpu *next)
> @@ -626,7 +649,7 @@ ENTRY(hyp_traps_vector)
>   *
>   * Returns prev in x0
>   */
> -ENTRY(__context_switch)
> +FUNC(__context_switch)
>          add     x8, x0, #VCPU_arch_saved_context
>          mov     x9, sp
>          stp     x19, x20, [x8], #16         /* store callee-saved registers 
> */
> @@ -647,6 +670,7 @@ ENTRY(__context_switch)
>          ldr     lr, [x8]
>          mov     sp, x9
>          ret
> +END(__context_switch)
>  
>  /*
>   * Local variables:
> -- 
> 2.40.1
>